Re: Worth it?
I have an idea of how it works, I was in the army for 5 years and have taken part in a few NATO exercises and joint operations. Mostly it's a case of 'That's your bit over there and this is our bit over here'. I really don't see any truly international fleets happening a y time soon, particularly with Brexit parting us from the economic aspects of Europe. That alone could lead to some grudging cooperation.
It would make more sense if Britain wants capital ships to build the support that goes with them rather than hoping everyone else will give us a hand, or not.