What's the point of getting transformed?

I found a crazy machine in the lower level that appears to turn me into another species. I wandered around for a bit after my transformation and tried switching back and forth a few times, but eventually decided to remain as my old self. I came back later and tried again and this time I turned into a different species from before (I think).

Other character dialogue doesn't seem to change when I'm transformed. Is this just an aesthetic thing?

For reference, this is what I looked like after my second round of visits to the machine.

In Capitol Town are members of the Ramble Planet's 3 main species. Each of these holds a PART that they will only give to someone of their species. The transformation machine can change you into a HOLDBOX, DROPBULGE, or PALSINK through repeated use. Changing into those races is necessary for talking to those people and getting the PARTS they possess.

However, the transformation machine sometimes just changes you into random species outside of the 3 main species. Being the tripod alien, the big head alien, or the spiny alien won't help you get those PARTS, although I think they look the coolest.