I almost always prefer to say "yes" (or, often, "yes, but...") rather than "no," so I have no inherent opposition to making a +4 (or higher!) weapon. But any fancy weapon someone picks up, I want it to be meaningful.
Weapons in Dungeon World can theoretically have whatever +N value you as DM want. +N doesn't affect accuracy, just damage. (There's also "P piercing," which ignores P amount of armor, since AC is DR in this system.) But since HP values are always pretty low, I think the absolute highest HP I've ever fielded at the party was less than 30, a large +N value is still pretty handy.
In my game though...I have striven to make all the tools and weapons the party use feel weighty and important. The Druid found a living acacia-wood "staff" early on, which turned out to be an artifact scythe that had had its blade removed. He's on a quest to restore it, and the material he chooses for this purpose will have significant symbolic consequences. The Ranger has found a bow, which he has since discovered belonged to his inheritance-line ancestor (major reveal there), the First Sultan, thousands of years ago, and if he can collect all of his ancestor's treasures (thus far bow, cloak, and spear), their powers will collectively grow. (It's somewhat a magical/supernatural inheritance, since biologically something like 90% of all humans, orcs/half-orcs, and part-genies should now be at least a little related to him.) The Bard has acquired a genie-wrought sword, Risha al-Ghurab, the Quills of the Raven, which interplay with his performance-magic and his flirtation with the shadows, and helped build into his eventual (not entirely willing) assumption of a prophet-like leadership position for an assassin cult. (He's trying to reform the faction that believes he's their prophesied destroyer-savior, and stands a good chance of succeeding.) The Battlemaster has a sword, inherited from his elven ancestors, with mysterious powers to "steal" the abilities of enemies and weapons he defeats. This has since been revealed as one of the "keys" meant to return, from some planar refuge, an ancient culture of eladrin (who are somehow related to elves, but not clear how--those eladrin who did not depart the world "became" elves.) The blade is certainly powerful in its own right, but it also invites deeper questions and advances a story.
So...if I made a "+4 weapon" or the equivalent...I would want it to be similarly "epic." Something that would communicate that it's not just a particularly sharp sword--that it means something. Or, hey, maybe I could lean into its lack of meaning. It's absurdly powerful, covered in symbolic images or unreadable etched runes, it HAS to be super important, right? Could be an interesting subversion to have a de facto powerful weapon that's literally just a powerful weapon, no special strings attached, but that you must complete a long journey of discovery and adventure in order to learn. Not quite a shaggy dog story (since the weapon is still powerful), but perhaps that could be an interesting direction if anyone new joins the group.
Both sides of the discussion about very high-plus weapons tend to lose sight of this stuff. Critics tend to think of it as pure powergaming, grubbing for every little bonus or secretly hoping to be stupidly OP. That is, critics assume fans of such things are completely uninterested in good story, so therefore it's categorically better to use low- or even non-plus items (or other random wondrous items), since such items are obviously inherently more story-filled. Fans delight in the power but, because discussions like this are necessarily shorn of context, have no stories to hook into, and thus don't talk about them much. Can't assume you know what any given campaign's story will be, so playing the character-creation "game" necessarily involves saying little about things that will depend on a host of factors you can't predict. Obviously best to say nothing at all about stuff just in case it might prove incorrect, right? (Not that the internet has ever encouraged anyone to behave differently...)
Good weapons--good magic items--have some kind of story. It doesn't have to necessarily tie into an epic quest, nor be an insanely powerful artifact. The aforementioned Bard loves his simple, portable battle-drum set with a vigor enchantment on it. Despite sometimes having memory struggles, he's never once forgotten he has them and delights in finding new and creative ways to employ their health-boosting effects. A +4 (or whatever) sword could bring in ancient legends and lost history. Or perhaps it has no history at all, as it defies what was thought possible, and its sudden appearance is a sign of some major change. Or perhaps it's the calling-card or token of some dangerous being, and even associating with it is a risk. Or perhaps it's a powerful tool but also a critical component of something else, forcing the player to choose between keeping their Cool Sword and using that sword to accomplish something they deeply, deeply care about.
I could probably go on naming more possible stories, but I've made my point. There is no more nor less story inherent to +N weapons vs more qualitative enchantments or non-combat magic items. The story, the true value, of these things comes from what we--as DMs and as players--do with them.
