Is this a faster way of doing things?

Is it faster to install hassio on a windows PC first, and then when the “development” is complete transfer the image to a Pi3.

What I found is restarts of home assistant is pretty slow, although once everything is bootup everything is snappy.
During development, I’m pretty sure the most time consuming time is the restart so does it make sense to run it in windows first and then migrate to pi once things get stable.

For sure man! If you have critical services running on your rpi you don’t want to be rebooting unnecessarily while testing new features.

I suppose you mean to install hassio in a VM?

Yes.

The assumption here is that the restart time of hassio using windows with a i5/i7 processor is significantly faster and everything in windows loads faster.

I just want to make sure that my assumption is accurate.

Are you restarting the home assistant container or rebooting the whole RPi?