@helene software architecture. wherever possible, features should be portable, not specific to one app. The unicode emojis are standard, they work everywhere without implementing any special support for them. custom emojis have to be downloaded for the client to render them, and even if they are supported on every fediverse app, they’ll never be supported on apps outside of the ecosystem, so you can’t copy-paste them like you can with regular emojis.
I also think that emoji reacts themselves are bloat