really not sure why anyone would use TSS for anything larger than a 20 gauge.
There are actually several good reasons.
1) You can get more consistent, more dense patterns with a
LIGHTER payload,
which can mean significantly less recoil in something like a Mossberg 835.
2) You can use a more open choke, giving greater margin of error for closer-range shots (long range as well), while either preserving or extending range.
3) For some, it is to increase range over copper-plated lead, even in a 12 gauge.
4) Using TSS for turkey hunting doesn't necessarily cost much more than using "cheaper" lead loads.
This is in the context of our total turkey hunting expenses, and only firing 3 to 6 rounds or so each spring. Spending a few extra dollars on a few rounds that provide better odds seems reasonable.
If I want to save a few dollars, I'll cut out something else.
Seriously, one meal in a restaurant, once a year is about all we're talking?