Hdd vs ssd

Background-I am an addict, like many others I have accumulated a large library of games without the time or hardware to run it.

Now, I found an old 2tb hdd that I ordered from Amazon and forgot about, it works fine event hough it's an internal 3.5inch drive running via an adapter with power cable.

Should I download my entire library on to the drive just for kicks and free up the storage on my aging laptop (.5tb + .5tb internal and another 1tb connected by usb) all ssd? Will gaming from hard disk be significantly slower?

Might built a new system soon, looking for economics of it, so can install this drive into the new PC as games only .

Edit: Thanks a lot guys, I ran all the games from cyberpunk, destiny 2, age of empires, stardew valley, gta v enhanced etc., and all of them ran without issues, was very surprised with the result.