There are benefits and disavantages of making pixel art on a website.
Plus, the fact that most YouTubers are using it means that it will make collaborations seamless when the time comes.
If you are looking to get started with Final Cut Pro X here is a very nice 20-minute tutorial to help you out.
After black and white came 8-bit colour, leading to the distinctive 8-bit pixel art that we know today.
Online pixel art apps like this one allow you to create pixel art on a simple grid and instantly share it with friends.
That is one very powerful advantage to keep in mind.