During MAJOR events like earnings and breakout news events, after-hour trading DOES have advantage as prices tend to move further during the next regular trading session. So if you are lucky and are able to get in on a trade at a better price during after-hour trading, then you can profit more when the next session of the regular trading opens. Even if the price doesn't move that much during the next regular trading session, your loss would still be limited and you will still have a chance to make a small profit.
But this is only during MAJOR events where the price moves like 10%+ which is rare. Most of the time when the price just moves at most 2-3% and not even, it's not worth it to trade after-hours. Due to the EXTREMELY bad liquidity, you could get in on a very bad fill and you are going to lose money.