No just that, but whether or not Mars is still geologically active is still an open question. If you admit planets on the basis that they have a history of geological activity, then Ceres is a planet too.
I don’t think anybody considers geological activity as particularly useful for classifying things as ‘planet’ or ‘not planet’.
Why shouldn’t Ceres be a planet? If Pluto gets to be a planet then Ceres is definitely a planet.
But there is still active geology on Mars. There is still moisture, winds and ice-caps that are shaping the environment. I consider that to be geologically active.
EDIT: And there are actual experts which consider active geology (or something similar) to be a planet, including Anton Petrov (https://www.youtube.com/watch?v=8-2HxrgqUnM)
Okay, but then you have to go and figure out which other asteroid and kuiper belt objects are planets.
The 'dwarf planet' distinction helps solve this! There are planets - distinctive in that they have clear orbits - and there are dwarf planets, which can be part of belt systems. This is a useful distinction.
Sure it is, but the distinction between terrestrial planets and gas giants are also useful, that doesn’t mean the latter aren’t planets.
I think it is fine that there are more objects planets then we can meaningfully count. Loads of things in our language act like that. E.g. a bug can be any number of things, and you know what a bug is by just talking about it. If some insect society then comes up with a meaningful definition of bugs which excludes spiders, that definition isn’t really doing the average user of that word any favor.
I don’t think anybody considers geological activity as particularly useful for classifying things as ‘planet’ or ‘not planet’.