Betting on both teams (also called arbitrage betting or middling) can result in the bettor making a profit regardless of the outcome by placing one bet per each outcome (and with different betting companies). Again, the conditions must allow it.
Are side bets in blackjack worth it? Side bets can be entertaining and potentially offer higher payouts than the main blackjack game. However, they also have a higher house edge, which means they are riskier in the long run.