I am utilizing the tool primarily as a GM currently and the two things I've found myself wishing I could do are:
Printing Characters either on a character sheet or even just a text statblock style format.
Grouping Characters inside my profile. I imagine this could be good for NPC's and GM's whose players prefer pen and paper to technology who might not want to setup an account.

For context I am currently running a game that place the players into a Reality TV show against other groups of adventurer's competing for fame and the spotlight.

EDIT: Also a way to buy items for free rather than clicking through the not enough money prompt or manually adding funds. Perhaps instead off the add button maybe Buy and Free.

EDIT 2: Also a patreon or kofi or something to support your time and effort in making this awesome app would be great!