Stasis 12 has 2 end game set ups:
Stasis 12+Thermal Lance 6 on a fatboi like Juggernaut
Or
2x Stasis 12(has to be 6 stars) on Panther, to absolutely crush CPC games.
The 16 cost version has faults because nothing can ever run two of them, and thermal 6+ Stasis 16 on a 24 EN bot is kind of a waste.
Between the two versions of stasis, the 12 cost version is definitely the one that will get more mileage unless you intend to run Carbine/Pulse 8 with the 16 cost version on a 24 EN bot.
The AI tends to use Stasis 12+ TL4/6 at my level, and it's a royal PITA.
The stasis beam is more of a CPC weapon though. It might have a hard time securing kills in tournament on pretty much every map but the huge wide open one we have this week.
Ultimately up to you. I'd honestly bookmark it as something to bring up after obtaining all of the high DPS rank 5 weapons. Might be better served spending that money on the coins+crates deal, and keeping the coins bought as a booster towards reaching Carbines/rail gun/rank ups.
Tournament is the only sizable resource cache to be obtained through in game effort, so any item that isn't maximizing tournament performance is kind of wasteful until you've bought all of the most effective damage dealing items.