Bulbapedia is nice when you want everything, which I actually often do for some of my projects. I do need to know what its based off of. I do need to know what it learned in every generation. I occasionally even need to know the anime bullshit. Like, for most people, Bulbapedia should not be your first source. However, it has its place. For example, I am currently making a giant Google doc on the ecology of the Alola region. Wouldn't it be nice if a site had a section on biology? Oh wait, Bulbapedia has that.Bulbapedia is also laid out horribly. They only semi-recently (like within the last couple years) moved game data higher up in Pokémon species pages instead of having that info buried below a bunch of extraneous crap (e.g. anime stuff) that you have to scroll through when it is probably what 99% of people check for when visiting those pages. And even then, stats and movepools are still like at that bottom of the game data section for some reason.
But at least they're not Serebii lol. If I'm on Bulbapedia I can read the site coherently, find what I want (even if it's not laid out well), and easily clink page links when on my phone. Serebii is just a disaster.
I switched to PokémonDB for when I want to double check anything related to stats quickly.