HMs were born from the idea that surfboards and other 'normal items' were phased out in favor of having the Pokemon complete overworld actions. It was meant to be more in line with the idea of being a Pokemon trainer and therefore more interaction with the monsters, but it's kind of a mixed bag.
1. Obviously inconvenient as fuck.
2. While it's in line with the idea of Trainer/Pokemon as partner, it does also just take away from the agency of the trainer. It's a weird direction we're seen the entire series phase over towards, though. Red/Gold/etc. used to be independently as competent as any other video game protagonist, in terms of having a bike, a cool watch, buy shit at stores, etc. but now the bike is a Rotom Bike, your watch is a Rotom Watch, there's a greater proportion of items that are used by/obtained by the Pokemon rather than weird JRPG items bought and used by the protagonist, etc. It better aligns with the core focus of the games, but it's part of the tonal difference between Gen 1/Gen 2 and everything since that probably plays a part in why the nostalgia is so strong for those games.
