If it doesn't come at the expense of battery wear, then sure, lower charge time is just better. But that would make phone batteries the only batteries that don't get excessively stressed when fast charging. Yeah, phone manufacturers generally claim that fast charging is perfectly fine for the battery, but I'm not sure I believe them too much when battery degradation is one of the main reasons people buy new phones.
I have no clue how other manufacturers do it (so for all I know they could all be doing it right and actually use slow charging), but Google has a terrible implementation of battery conservation - Pixels just fast charge to 80%, then wait until some specific time before the alarm, then fast charge the rest. Compare that to a crappy Lenovo IdeaPad laptop I have that has a battery conservation feature that sets a charge limit AND a power limit (60% with 25W charging), because it wouldn't make sense to limit the charge and still use full 65W for charging.