Hiya!
You say that, and I'm inclined to agree, but the reason I whipped up these XP values was more so that I could figure out how MANY traps to put in my dungeon. I wanted to know how a trap compared to a monster in terms of using up party resources. The DMG does a good job of saying what the ramifications of putting in a trap might be, but it's hard to judge how many or what strength of trap to use if you want traps to be something the party is expected to overcome as part of a general adventure.
Like, if I'm throwing down a deathtrap dungeon, how many traps do I put in it? Where? What happens if there's some monsters in there too? How likely is the party to die horribly in this, and how likely are they to survive?
Plus, in terms of looking at XP as an award for overcoming challenges rather than just an incentive to fight, traps are definitely part of the challenge of an adventure, and a party who isn't interested in combat should be able to get XP from cleverly defeating traps and tricks as much as they would for cleverly defeating goblins and orcs. It's hard to account for that without trap XP.
The problem with this is much like the CR system; it more or less becomes a
"well, I'll have to just guesstimate XP the value" the instant that the parties 'condition' changes. A trap is worth X amount of experience. This assumes 'perfect situation'. What if the party only has Dim light? Oooo....now the find traps check is at disadvantage...so that makes it much harder...is it then worth more xp? How much? What about if the Ranger casts
Find Traps? Is the trap even worth any XP then? What if the party doesn't have anyone capable of detecting traps at the moment? (say the ranger doesn't have that spell and the thief is dead/unconscious) The trap could be a potential TPK...if the party survives, do they get any XP for surviving it? Do they get nothing?
In short, there are FAR to many "What If...?" situations for traps. Right now I'm more or less running "90% by the book" because it's still new to me. That said, I'm finding myself making more and more DM decisions for my campaign (how 'natural' healing works, how/when class-level training is needed, etc.). I, and my players, are becoming more experienced with how 5e works and we are adding in our own preferences...as expected, and as it should be.
I've never been really happy with how XP is handled in D&D. The best XP systems I've seen are from Palladium Fantasy, or from Powers & Perils. Palladium hands out XP based on 'actual game play results' (e.g., if a fight is barely won, it's worth more xp...regardless of what was fought; coming up with a clever idea, successful or not, is worth xp; making everyone laugh at the table so much that everyone has to take a break to wipe the tears from their eyes and catch a breath...you guessed it, worth xp). Powers & Perils does give XP for monsters, but it is based on how difficult the creature is as well as how much danger the character was in simply because how much damage they do to the creature determines how much "Combat Experience" they get; all skills get better as you use them...e.g., how much "combat" you get in is irrelevant (except for your combat skills used in that particular combat, like your Sword skill or Shield skill). Magic is handled similar; defeating opponents and casting magic makes you a better magic-user, but you only get better in spells that you actually cast (same as the skill system, basically). With these systems, "xp from traps" is handled automatically; you get better based on the actual danger posed (Palladium), or if you succeeded or not (P&P). No need for "trap XP values" as it's handled in the system already.
For D&D, I'd go with Palladiums way as it is a 'closer system' to D&D than P&P is.