I haven't tried the kind of narrowboat holiday you describe. I have heard of some where you can just go along as a passenger and all the work is done for you or can muck in if you wish.
Late DH and I used to hire narrowboats, just the two of us or with another couple with whom we were good friends. We did all the helming, mooring up, lock work and cooking ourselves. I loved these holidays just chugging along, stopping along the way for a walk or to visit canalside villages and pubs, mooring up in the middle of nowhere for the night. My favourite canal was the MonBrec as it's so peaceful.
I do find canals and locks fascinating and enjoy operating the latter so, yes, I can understand why you might like a trip which is somewhere between luxury and nerd.
I'd give it a go. You'll be living in very close confines with strangers for a few days with not a lot of privacy but so long as you don't mind that it would be good introduction to this kind of holiday and lifestyle.