Not so much a move as an addition. And there are a few reasons.

One, I like projects where the outcome is a useful tool, but the project aspect itself is a significant part of my motivation.

The reason for the Voron being that project is that it will be a WAY faster and more competent tool than my ender, which was a prohibitive limitation especially for larger prints. A failure at hour 23 of a 24 hour print sucks, but the same print failing at hour 3:45 of 4 hours is way easier to accept. At that point the loss of filament matters more than the lost time in my eyes.

Also Voron2 has a much better design than ender 3 pro for exotic filaments, making ABS / ASA / nylon more approachable. Better tuning options, compensation (lower / less moving mass), bigger plate, taller build volume.

The bigger plate is significant for things like ergo mechanical keyboard chassis. I'm a Dactyl Manuform user and builder, and the ender 3 pro can only print one half at a time and takes more than a full day each half. Voron should be able to knock out two halves at once inside of a work day, and do so with better quality to boot.

The ender still has a place, particularly with the mods I have on it. Specifically, TPU can't benefit from the speed of Voron, so there's no reason not to print it on ender. Also it never hurts to have a tuned, working machine if you have to take one offline for maintenance.