So what's nutty with this card that differentiates it from Nihongai Grid is that "no unspent clicks" clause. That allows you to use An Offer You Can't Refuse for a "damned if you do, damned if you don't" effect: give the corp an agenda point, or let them score an agenda out of hand next turn. Any sensible runner will let you do the former unless it will win you the game, and if 1 point is enough to win the game Manta Grid ensures you win the next turn. Manta Grid is the most realistic and effective combo you can run with An Offer You Can't Refuse, granting you a Biotic Labor at less influence or a 1 point agenda for fewer clicks.
How to use this: Harmony Medtech: Biomedical Pioneer. Between Medical Breakthrough, Clone Retirement, Braintrust and Philotic Entanglement, getting to 5 points has never been easier, and Manta Grid lets you close the deal without taxing that 12 influence too highly.