The way I understand Remarkable is I get to live in their silo. Mostly meaning you’d need to manually export any file from their cloud into your own preferred locations and tools. That is akin how it is now using paper, a barrier requiring manual intervention. If there is no fluid connection to the rest of my digital stuff, it’s not a useful work device.
There are a few tech differences too (e.g. 32GB vs 8GB storage)