The thing I like about race-as-class is mechanical simplicity, especially when doing character creation with new players. I don't like how in 5e you get skill proficiencies from possibly three sources (race, class, background), and some might overlap. I find that ribbon abilities (gnome tinker, stonecunning) are to niche to be useful, and saving throw bonuses to specific kinds of spells or damage easy to forget. A lot of what's in the races is there just because it was there in 1e and is part of the heritage, except most races get darkvision because you're really playing a 1e style game where vision/light matters. This is before we get to the incoherent worldbuilding, the rapid expansion of races, the fact that neither the implied or default setting (FR) tell DMs how all these humanoids fit together in a cohesive way, and of course the issues of essentialism. I'd rather races/ancestries and cultures be tied to particular settings than part of the kitchen sink.