The turnbuckles shown use dissimilar metals in the housing and the threads as to prevent cold welding. These are intended to be adjust while under tension and won't seize up. The bare terminal threads and nutts do not have this feature and can seize up. An added issue with the latter can be that the threading is simply ripped of the terminals if the nuts are tightened. The bare threads/nuts setup doesn't have enough revolutions to spread out the load sufficiently. The latter is the main reason I'm told to detach your diamond wires before adjusting them.

I say :"Put a pair of turnbuckles on my boat, I think I can survive the added 150 grams (1/3rd lbs)and 30 bucks in costs"

Remember the saying ;"pennywise, pound foolish"

Wouter