As a means to outsource SHA256 cracking it would be patently useless. To crack a hash you need a collision. Bitcoin mining doesn't produce collisions, it produces "hash is smaller than target" results. But even if you'd assume there'd be a value in that answer, it's still useless, because you can't dictate the hash of the previous block (which is included in the hash of the current block), and you can't dictate the transactions of a block a miner would include (which also go into the hash). Since you can neither dictate input nor output nor get a collision answer, it'd be a pretty stupid tool for attacking SHA256.
It would also be useless as a means to attack EC-hashes, since miners don't try to guess these, and the flavor of EC-hashes used in bitcoin is unique, it doesn't overlap with the ones usually used in TLS.
See this is the reason why people who're not programmers shouldn't comment on things todo with programming. Especially if you've never designed and implemented a protocol, you shouldn't comment on protocols. If you've never used cryptographic hash functions, you shouldn't comment on them. If you've never understood the bitcoin mining process, you shouldn't comment on it. As a general rule of thumb, don't comment on things with conclusions, you can't support, because you have no clue.