You start to appreciate Pro Motion when you think 'gosh, I wish there was this sort of specific feature coded in it' and then you realize it is already, and it's useful, and you grow attached to it and then you try GGale and it doesn't have it and you have to do that same thing by hand again. It's like Photoshop in a way (for image editing). If you only use Photoshop for very basic things, the rest is bloat. But if you're interested in doing complex things efficiently and faster, Photoshop has features you'd probably like.
The fallacy is that because pixel art deals with a basic entity that is easy to manipulate in any program (the pixel) then every artist approaches making things with pixels in basic ways. It isn't so. There's dozens of little helpful things in pro motion for any artist that is serious about their work and willing to dig through the documentation to try them out. If you're not adventurous, you don't need it. Stick to GGale.
The danger of course is getting carried away with inexact tools in Pro Motion and arriving at faux Photoshoppery by way of index painting. And then arguing with the lesser informed about how what you did is all 'hand-pixelled'. But that's a moral boundary, not the fault of the program in any way.
Ptoing is right, I am ok-fast, but I could be faster if I sat down with the program more and learned it more. When time allows I will. Pro Motion is near inexhaustible as far as smart little features go and more keeps getting added because Jan listens to artists. GGale is for me, a great option for beginners. MSpaint is just some sort of strange sadistic joke.