Sometimes you'll get value out of him on Mines, but you'd be better off with someone else 9/10 times. The issue with Tass is he provides a bit of utility, a bit of waveclear, and a bit of damage. Most of the time, someone capable of specializing in one or two of those roles is going to be a significantly better choice than someone trying to jack of all trades three.
It also sees some use in anti-dive comps where you have one or rarely two heroes you're trying to protect from a Kerrigan/Zeratul/Butcher, where their win condition is killing that hero and yours is keeping them alive for more than ten seconds.
So, not never, but pretty close in most situations beyond coordinated play.