Oh, I actually made all of these accounts just to come to terms with the granular differences (and interactions) between each platform. The main reason I have all these accounts is to run little experiments to see how all the functionality works and to try underutilized features that I wouldn't normally touch on my main fediverse account.
My hope is that I can come to a more informed decision about which platform I should use long-term for my main account. Migrating just to try out something new can be challenging, after all. I also want to determine whether I should bother having more than one fediverse account.
Sure, in order from left to right: