Shot blocking can be very useful when your primary D skills aren't that great.
This is a very rare situation in the national teams, because there usually are top players.
It blocks a lot of shots and it impacts both outside and inside shots. It is also much easier to grab defensive rebound after a block I think.
In theory yes, but I don't see it works in that way in practice. In my team I have player with ID 18 and BL 18 but OD only 4. In theory he should be very good in inside defence and his blocking should help him to block outside skills. In practise he has only 1-2 blocks on average more than players with blocking on 6-7 level and he defends outiside shoots of bigs with good outside shoots very bad. Actually, im my opinion he isn't very good defender. Players who play against him has efficiency of shoots more than 50%. I would prefer instead of blocks more IS, ID and RB (assuming the same salary)...and of course OD minimum 10.