i personally don't use boosters but i can see how they can be helpful. on the digging levels sometimes there is a boost that will dig through a meter of the brick and is offered for coins. but i don't always get close to the bottom so it'd be a waste of coins for me. and if you do happen to change your mind and decide you want/need the boost once the level starts, the cost turns into gold.. haha. so i just ignore the boosts and try to pass without them. but for the fire levels in abode ablaze, looks like it's mostly the reshuffle and that activator of special jewels that is offered for coins. i don't even know if that'd be helpful? hum actually the activator of special jewels might be useful, because i've had a blaster land in the perfect spot but i didn't have any other matching color jewels to activate it. darn.. maybe i'll try it out in a future fire level
it'd be especially handy in those levels that have gaps on the board that make it difficult to target fires directly.