So what precisely is the benefit of playing a Half-Elf or Human?
There isn't one unless you're using a build that wants those new innate proficiencies while also not getting them from your class. If you're not doing that, there is essentially no reason to pick a human or half-elf over a regular elf, outside of RP reasons of course.
I have not seen it confirmed anywhere exactly what the "compensation" for humans/demi-elves/mountain dwarves actually is, but from the speculation I have seen, I don't think the racial attribute system changes make much sense.
Similarly, I seen no evidence that you can roll for character attributes (per PHB), which to me is an essential option for developing interesting D&D characters, particularly when rolling attributes in order, and designing the best RP you can from that. I particularly dislike the point-buy system in 5e/BG3 where you cannot reach extremities for the attributes; give me 3-18 any day.
As for the question "why make this change?", the answer is likely to be trying to appeal to the largest audience possible by being as "unrestrictive" as possible. Judging by comments on forum platforms like Steam or Reddit, many modern gamers ( i.e. the people that pay the bills for WotC and Larian, among others ) have the attention span of a gnat, or the entitlement of a lord. It's hard to cater for everyone, but if your cost base is high ( or you simply have an appetite for profit ), you need to reach as many people as possible.
If I were to speculate, I would say this is in keeping with the WotC direction of travel, not a Larian invention. WotC are always looking to modernize and streamline their IP. No more good and evil, no more law and chaos, no more racial stereotyping. I get it, the echoes from the real world are tangible, but I doubt that making a fantasy gaming system ultra-inclusive and politically correct will shame the world's leaders into better behaviour.
I agree that there is no real reason for not including both racial bonus systems ( given it only affect YOU as a character being generated ), as well as including all the PHB basic attribute generation systems. By all means have a default system that is simple and quick to use for the majority that don't care, but there is no reason why alternatives can't be enabled in the settings. Character generation is one-and-done; how you generate your stats affects nothing in the subsequent game, and therefore comes at a minimal development cost. Certainly that cost is trivial compared to the enormous efforts to produce the overall BG3 game, and even trivial compared to the effort required to allow the mind-boggling complete cosmetic choices during character generation.
Is it of realms-shaking import? Probably not, but it will definitely lower my opinion and rating of modern D&D (and so BG3) to continue removing the elements that made it interesting in the first place.
