I get your idea and if it works the way you want to it's all good.
I have something similar. But I just put a tee with valve on the existing 1/2 toilet supply line. I then have a short garden hose always attached. I saw no need to run a 2nd dedicated line into the bathroom?
I can use the garden hose as a turd blaster or a toilet filler.
The garden hose has a lot more pressure than the toilet rinsers found on many RV toilets
That 2nd dedicated line might be good for winter camping? you could fill and flush toilet without putting water into the entire plumbing system!