Do you guys actually need these tools / batteries? Or are you buying them just because its a deal / hackable?

I guess what does actually needing something really mean, right? But the amount of people running out and buying these 3.0s and 5.0s has me curious what yall are using them for or why you need so many of them.

(I did not get any batteries today since I recently got the $119 2x5.0s (I know todays is a better deal..) but I did get the M12 Rover light)