I hotswap drives all the time, it's not a problem and makes a harddrive swap a 30 second task instead of a 10 minute task and doesn't incur downtime either.
Most consumer hard drives (and indeed bays) are not designed for hotswapping and it can cause damage (though maybe modern build quality is good enough that you'd be lucky most of the time). "Downtime" on your home server in your closet is a minor inconvenience at worst.
The SATA connectors are designed for hotswapping, the ground leads are longer than the others so you get nice properties when connecting and disconnecting. I'd be mildly concerned about properly stopping the drive that's being disconnected, except it's probably being disconnected to be replaced. I don't see much difference between connecting a drive and turning the power on to an already connected drive.
I use NAS Harddrives which are built for hotswapping. I have no idea why anybody would use a consumer harddrive in a RAID Array, the price difference is 10€ at best AFAIK.
For a home server what's the benefit you're paying for though? I don't need max performance (I use RAID for redundancy rather than anything else), and a little downtime when I replace a disk isn't an issue.
If you have several drives in the same bay, you're going to get vibrations that severely reduce lifetime of the harddrive. NAS Drives also have much better electronics/mechanics to help them not crash all your data while in use. They won't try to heroically save that one sector and report to your RAID controller instead, meaning you get a much better overview of harddrive defects and lastly
Lastly, NAS Drives have a much lower error rate than Desktop drives due to the usage of higher quality heads that increase error resistance and lifetime.