I meant that to say, it's a genre that deserves to be distinguished from just one of the many games that define it.

As a rephrase of that comment, defining the 5 games I listed after one game that basically just came before them would be dishonest because of how different those games all are from Slay the Spire and each other. That's why the genre is named after what they all have in common, which is a mashup of two existing genres.

What you're proposing would be like renaming the first person shooter genre to "halo-like" or "call of duty-like" just because those games predate a lot of others and people like them. It's unnecessary and loses the descriptive quality of the name it has.