I have to admit I have also switched back to real paper for a lot of tasks but I still like the remarkable as an e-reader, and enjoy writing on it occasionally, so I wouldn't say it's a big regret.
I'm also using a lot more paper and have gotten into fountain pens for some kinds of note taking, which is about as economically ruinous as mechanical keyboards.
In the future, I have it on my list to change it into an eink linux box to use to connect to remote machines with the attached keyboard. At least the hardware will be used eventually. Probably won't use the pen in that configuration.
BUT -- I can't remember the last time I charged it. It's possible it's still on its original factory charge from a few months ago. As someone whose phone is perpetually below 20% charge I greatly appreciate that feature -- given the choice, I'll always choose "needs to boot" over "needs to charge". Your anecdote has therefore reduced my own buyers' remorse.
I turned them off one time and it wouldn't even last a day, but after enabling them back again it's back to it's normal multiple days battery charge.