Better? That's probably for the users to decide. But it will probably work better, especially if the user used a recent rclone version on their computer.
The fork is actively supported, meaning that it has fewer bugs (some not verified in the original) and security issues and more features. It has also been updated for Android 10 and newer rclone versions, with support for 1.50.2 in the current release and 1.51.0 in testing (compared to 1.44 original). You can also avoid sideloading by registering for the Google Play distribution test.
For the "full" rclone experience, I would always recommend using Termux - which is why I've been working on sharing configs between termux rclone and the app.
No, only if you don't know the CPU architecture of your device - details
EDIT: missed the second post - but I pretty much already answered it