Wow I'm so happy to have found this. Have you considered clubs, restaurants, cafes etc as a target market? If you wanted to start earning some revenue to host it I think there could be an opportunity more so than home users.
We had started down the track of building a basic version of this for our ski club using MS "Power Apps". Our basic process is:
1. Pre-season: estimate requirements based on previous years and do a few large orders with various suppliers for delivery to coincide with the annual food lift (we can't drive all the way to our club). Primarily this is meat and non perishables such as tinned/packaged items, toileteries and cleaning products.
2. Every few days during the season: perform a stock take of what's on-hand in the club. Send to the catering officer.
3. Catering officer orders according to his/her assessment of requirements. Mainly this will be perishables such as fruit/veges, eggs, bread, milk but later in the season may include other items
4. Items are delivered to common stock room and carried up the mountain by club members. Items are checked off the order list provided by the catering officer and added to various storage areas (fridges/freezers, store room, kitchen pantry etc).
Based on a quick run through the demo system I think grocy will meet our requirements for managing consumables.
Additionally club members staying on a particular night are assigned duties by the lodge leader e.g. breakfast dishes, vegetable prep, cooking dinner. We may be able to use the "Chores" function to help with that.
Personally for home use I would not use this because it would not be practical for our family.
Regarding an additional feature: I would recommend looking at Cozi which we use for a shared family calendar which is really valuable for us. I imagine it would be fairly trivial to add that feature to Grocy.
I'll let you know how we got on with the club. Thanks and hope that helps.