Originally Posted by
Seirin
While the idea of a distraction is all well and good, I personally don't much like the idea of a suicide brigade. Marines are only marines and essentially you'll be handing your opponent both a kill point and a spring board (charge + advance).
In my opinion, allies should offer an army something they don't already have. Libby aside, a tactical squad offers standard firepower - something Tau already have a lot of. If you were going to use this method, I would honestly keep the libby with your tau so you can prescience them, rather than sacrifice it with your tacticals.
On another note, have you considered allying GKs to tau? For the same price as 10 tacticals, libby and pod you could get 5 terminators and a better libby with a few points left over. This gets you both a distraction unit and a very solid close combat unit - something tau absolutely lack.