The only issue I could potentially see with doing this, would be with your bootloader. Not sure about other bootloaders, but there's potential for some weirdness with grub if both systems are trying to do their own thing and constantly overwrite each other's config every time you upgrade the kernel. You'd probably want to use something other than grub (although some of the others may have similar issues, so make sure you do your research - I think rEFInd used to be recommended for things like this, but it's been a while and that might no longer be the best route anymore) or, configure one of your distros to not automatically update grub after updates, but in that case you'd need to login to whatever system you still have managing your grub and update grub on that system, every time the kernel updates on the other distro.
But other than that, there shouldn't be any issues with dual booting both, outside of the fact that you'll basically have everything installed twice.