This sort of batch asset conversion can be pretty easily automated with some combination of scripting and/or makefile.

Taking the time to learn about these sorts of compression methods is well worth it, as once you start loading assets of any appreciable scale or number, the savings in asset loading times can add up to be significant, turning what might have been a noticable jarring pause or stutter into something much less noticable.

Think about it, with hardware texture formats, not only are you not having to decode the PNG on the CPU, but you're also literally uploading less data to the GPU overall, since it can be transferred in a compressed form.