I have read about some of the new systems for plumbing and they sound interesting, but I have no experience. On Alchemy, my guidance system for new things is, in part, “Does it solve a problem?” If not, I tend to leave it alone. The other criteria is whether a new system might it save work.
The hose clamp and hose system has always worked for us, so I have never considered alternatives. Working with hose and hose clamps, barbed fittings etc. can sometimes be a pain, but somehow always seems to work out and there are tricks learned along the way that have made the work easier and more reliable.
As for keeping the system usable with a faucet removed, I take an appropriately sized bolt, wrap it with electric tape till I can just insert it in the hose and clamped it. Isolation valves on a house system make sense as the piping is usually metal (or hard plastic) and de-pressurizing a whole household system is difficult. Depressurizing a boat’s system is no big deal and one is just dealing with hose ends.
If the flexi hose/stainless that you are describing is like the shower hose on some installations, I am not sure I would want that swinging below my sink all the time in dark damp places. Are there not alternatives?
My best, Dick Stevenson, s/v Alchemy