Bonus Buy can be a help for some people so they still buy that and hopes they can hit the jackpot. But they must realizes that Bonus Buy can't always gives them big wins so they must be careful spends their money to Bonus Buy. I prefer to playing as normally and not use Bonus Buy because that can makes me lose much money. I can forget to control myself if I often use Bonus Buy.
In my case, I prefer to purchase bonus play in SB. With only 10 free spins, I get a multiplier than playing normal or auto spin. Though, it has a fast phase that's why you most likely forgot to control yourself when you use the bonus play. In that case, it's better if you try to build up your own strategy. Just like what I did, it also happened to me that I didn't control myself in slots as I continuously purchased the bonus play, which is incorrect. Doing this will only make you lose money so fast without realizing it.