Jimbo is a TV personality and knows just as little as anyone else. The little positive correlation his recommendations have on a short term basis are from people buying in and pushing the price up. Casual market manipulation.
edit: Stop downvoting me. I did not realize parent commenter was OP of the reddit post.
Only 20 trading opportunities a day, fairly limited alpha on each trade (1-3bps), limited liquidity since you're just trading against the small retail population watching Cramer at that time, the possibility of getting picked off by another institution who figures you out...