I don't think its about game mechanics at all, or at least, not principally. Whether or not a class like a ranger uses magic is massively important from a purely aesthetic perspective, and has big worldbuilding implications. If you don't want to play a magical character, or run a ludicrously high-magic campaign, D&D has increasingly little to offer.
No, it really doesn't have ANY world building implications. Since the effects of what the ranger can do are identical to spells, then, from a world building perspective, it makes no difference. It doesn't matter if your animal friend comes from a "Knack" or an "Animal Friendship" spell when both are functionally identical.
I think that's one aspect. Certainly if you want to imagine your ability as non-magical, a requirement for VSM makes that harder to support.
But we STILL have a VSM component. That Knack from Level Up absolutely requres verbal, somatic and material components. The description of the Knack 100% details exactly what all three are. Now, since something like Hunter's Mark is verbal only, and, in fact, if you go through the spell list of rangers, most of the spell effects and components are mostly mundane and would be exactly the same if they were detailed as a "Knack" rather than a spell, then there is no actual difference.
Right.
And WotC rules say that the ranger's abilities...
...need V,S,M components.
...can be dispelled.
...can be counter-spelled.
...are subject to anti-magic zones, issues with The Weave (is that still a thing in FR?), etc.
...legendary resistance (haven't gone through all the spells, may not be thing)
...are part of other casters' spell lists.
Fair amount of rules interfering in the envisioning. YMMV.
Knacks/maneuvers need VSM components in Level Up and no one seems to complain. In 40 years of gaming I've yet to ever see an "anti magic zone" and since you don't even know if the Weave is still a thing, then obviously it's not impacting yoru games. And, again, having an Animal Friendship Knack that works identically to a Druid casting Animal Friendship is being heralded as the peak of non-magical abilities seems a bit strange. Paladins in 5e can have Hunter's Mark. Does that mean that rangers lose something? I've never once seen a single complaint about the fact that spells cross between classes as a reason for not having spells with a class.
As
@darjr pput it, it's not a spell. It doesn't matter if it's a copypaste. What matters is that the ranger can do, by dint of nonmagical knowledge and ability, what everyone else requires magic to do.
It's like the difference between someone who can carve a statue and someone who downloads the stl files someone else made and 3d prints the same statue.
It's a duck. Stop pretending that it's not a duck. It doesn't matter. The only thing that actually matters is the effect - how you achieve that effect never matters. No one actually cares.
This is just the 4e edition warring argument all over again. OH we can't have AEDU structure because it makes everyone a caster and makes all the classes the same! Which was 100% never true. A paladin most certainly did not play the same as a fighter or a wizard, despite using the same AEDU structure and anyone who played 4e for more than 15 minutes can attest to the same. Well, in 5e, we've made every class part of the caster rules. For years now, there have only been three subclasses in the PHB that didn't have spells.
You want a non-caster ranger, that has the exact same effects as a caster ranger, but, for some bizarre reason, needs to call it something else. It's difference for the sake of being different. It's meaningless. Instead of Hunter's Mark, you get Hunter's Target - exactly, word for word the same effect, same limitations, copy pasted from the spell effect, but, hey, it's not a spell.

For some reason I can forage for poisons exactly ONCE between long rests and make 3 doses of poison, but, I absolutely may not do it twice between long rests? And this isn't a spell? Works like a spell, has the same limitations as a spell and functions exactly like a spell... .but it isn't a spell. Or, I can see invisible for an hour, once, and only once per long rest, but, again, it's not a spell... despite being functioning EXACTLY the same as See Invisibility.
There's no point to any of this. The only difference between the OneE ranger and the Level Up ranger is the language used to describe it. It's exactly the same as the old 4e criticisms which ignored the fact that so much of 4e came forward into 5e, but, just with a different coat of paint.