What's difference between VBA and mGBA? They run the same, don't they?

Also, can I use MyBoy on mobile?

Why though? VBA, My Boy and mGBA run roms just as good. The roms don't run differently. I've tested in the past

Plus I've seen speedrunners use VBA on YouTube.

mGBA doesn't run well on my laptop, while VBA runs swell. Also, another question, is there a section for randomisers? If so, can you link it?

which category in there would I put any of my randomizer runs?