I don't see many of us forum users having need for a monobath but I can see it's uses....that's a nice hotel bathroom setup. Reminds me that some of my first experience developing contact prints from glass plates was sitting in the bottom of my parents' wardrobe with a box of paper, two of mum's roasting dishes (dev and fix)....placing a plate on a sheet of paper, opening the door for a count of ten to expose, then developing and fixing (no stop!) in the roasting trays in the dark, counting to sixty for each step. I was about 8. Actually a monobath would have been better for me!
I've considered developing films while camping, and while it's perfectly feasible I'm not sure what the campsite owners would make of me potentially using chemicals in their sinks. Plus my wife would actually prefer me to bring the films home and spend a day developing rather than doing it on holiday.....which makes sense. If I were travelling solo I'd find it quite relaxing and rewarding to develop a film in a hotel or on a campsite.
THe monobath is a niche product and not one I have any use for now, but I would have as a kid if I'd know such things existed. I bet a few people who want to get into film developing but who are a bit scared making mistakes would give a monobath a go before they felt confident to mix up powder developer and have separate stop and fix bottles.