Each player has their own preference. I do not say that buying bonuses is bad, it is that I wanted to have a longer session with my fund, so with base spins, the amount that I need to spend for Bonus buy will take longer to exhaust with base spin. Even with base spin we also have a chance to win huge especially when we trigger bonus round.
The budget for buy bonus is 100x from base bet this means if we prefer regular spin we have to hit the bonus or scatters in 100 spins if more than 100 spins means it's extra costs the same thing on buy bonus there is no guarantee we will get ROI. The conclusion is the bonus feature is a short way to change 100 spins to 1 spin while the final result depends on luck, there is nothing wrong with this way the choice is in our hands

This is the method I have used so far.
Buying bonuses will only give players a loss because when I first played I always relied on buying bonuses to be able to get big wins but what happened was that the funds used to buy bonuses increased and the results obtained from buying bonuses were uncertain or guaranteed profits.
It is very different when choosing a regular spin with a target maximum limit to be able to get a free scatter, sometimes when I have a target of 100x regular spins I can get scatters up to 2 or even 3 times which can return my capital along with a small profit.