Marketing on Instagram relies on a wide range of variables, and taking everything into account is of paramount importance. Most of the time when you check out your metrics you would notice an upward trend if you are posting regularly, but a lot of brands and businesses would feel like this is a little too slow and they would want to speed things up a bit by checking out some of the boosting options that Instagram offers. This would help you boost something that you have recently posted, and allow it to reach a much wider audience than might have been the case otherwise.
This is one method to boost insta presence, but you should try to realize that just throwing money at the problem is not automatically going to make it go away. Much on the contrary, there are a lot of ways in which you can maximize the efficacy of post boosting as well so that eventually you can end up with a lot more in terms of the kind of reach that you might get once the boost has been implemented and the results have finally started to roll in at the end of the day.
Captions matter quite a bit. Boosting is going to get you a lot of impressions, but it is the quality of your post that would end up allowing you to entice people into clicking on it and seeing what you have to offer. This is just one example of why spending money blindly is not going to do much for you, and why you should be careful and prepare accordingly so that when you eventually boost your post it would be primed and ready for what is to come.