Home run plumbing also means a lot of pipes in the walls, so you end up with 20x more pipes in the walls and ceiling than is actually necessary, and 20+ valves, which are often made of plastic instead of brass because otherwise costs would balloon. In any case, the fittings aren't the weak point, the pipe is; a properly crimped joint or expansion joint will never leak. And often it's impossible to have no fittings on a run of pipe anyway.

In my opinion, traditional trunk and branch plumbing is far more flexible and just as reliable. It also allows for a hot water recirculation loop, which is impossible with home-run plumbing.