My observation of halfling PCs is that people tend to play them in a way which is tonally distinct from humans.
I'm not sure how relevant lore is to all this (and really I think lore is a fandom fixation, not a practical game issue anyway). My observation has been in actual play halflings are much more distinct from humans than elves generally are.
Elves might have reams of really boring lore which you could actually read through if you have a bout of insomnia, but in games they are almost always played as humans that happen to have pointy ears and meditate instead of sleeping.
You might point to how elves are different to humans in the lore, but those are just words on paper. I very rarely see that lore translate meaningfully to anything that informs characterisation in play. The fact that your PC is 3ft tall and the size of a small child informs play in a much more concrete way.
As far as easily recognisable in play I would probably put Dwarves at the top followed by goblins, and then perhaps, gnomes, halforcs and halflings.
Tieflings, Genasi, elves and Half-elves (anything "human but cooler") tend to in play just be humans with cool powers.
And this really the basic structural purpose of races, a kind of broad rough strokes hook for play and differentiation.
Worldbuilding is really not the purpose of them. Worldbuilding with nuanced distinct societies is much easier without them.
Edit: A lot of people seem to be saying they don't know what to do with halflings. This seems to be from a GM's perspective. I've never seen players have that problem. (Of course if you do you just choose something else, but plenty of players over the years have known what to do with them). The PC races are not, and have never been there for GMs. Even Gygax supposedly didn't really want them, but he put them in for his players.
So if your problem as a GM is how to make a coherent world with the options before you, then you just have to do what GMs have been doing since the 70s. Solve your problems yourself. The game doesn't care. It puzzles me that people see these inconsistencies as problems rather than opportunites - I always though that the fun of worldbuilding in D&D was rationalising these things and coming up with your own takes and solutions.