Faolyn
(she/her)
Those are completely two separate issues.So, the iconic image of a tall and slim elf, a pair of slightly less-tall humans, a short and bulky dwarf and a handfull of small and not particularly heavy halflings is no longer a thing. Everyone is build within the much smaller range of humans. It is even more "rubberhead ear" than before. The "problem" it fixes is the complaint about "how can a 60 cm tall halfling have 16 STR when the 2m10 minotaur has the same starting STR? It's not realistic". The answer is: "because they have the same size and muscle/fat ratio. Your minotaur can't be taller than the halfling since both fluctuate within the same (modern Earth human) range". It's a logical consequence of floating ASIs, I'd guess.
The height/weight thing... I generally agree with. Although I should point out that in D&D elves are usually shorter than humans, which goes to show that the "iconic" image is not a universal one.
But I don't think that D&D would have lost anything by keeping racial physical builds. I'm pretty sure nobody is saying it's somehow offensive for elves to be slightly shorter (or taller, whatever) than humans on average. That being said, this does let people play skinny halflings or fat elves, if they want to, without bodyshaming either players or PCs for not playing a "typical" individual, and opens up the idea of particularly short or tall PCs--or even PCs with dwarfism or gigantism (I was in a GURPS game once with a gnome with Gigantism).
However, this doesn't actually "fix the complaint" about racial ASIs, though, because D&D is about a party of exceptional individuals doing exceptional things. Which means that a halfling with a 16, 18, or even 20 Strength is fine because this individual halfling PC is exceptional.
What's really funny is that the people who're against floating ASIs have, in my experience, already claimed the muscle/fat ratio (and general skeletal structure) as the reason for not letting halflings have a high Strength (or, apparently, allowing for high Int halflings either. I dunno, maybe they all read GURPS Biotech which included a suggestion of lower IQ for very tiny gengineered creatures?) Anyway, this indicates that floating ASIs and making all races physically similar are not, in fact, connected.