Sorry, but your Subaru isn't a line lock park brake. It is an eletric actuated park brake. I have seen several other cars that are the same way. Started about 10 years ago on some German luxery car stuff.
A T-case park brake is fine. Biggest issue is lack of clearance between the yoke and the floor. Very limited in diameter. There are a lot of larger trucks that use a rear of transmission driveshaft park brake.
So you go wheeling and break something in the rear axle or the driveshaft, guess what, the park brake will still work. Put it in 4WD and it will lock the front axle. Considering that you were probably in 4WD when you broke the parts anyway, no big deal.