They were for me.
Almost all of the shareware was on 3.5" floppies at first. So games like gorillas, scorched earth, doom, etc. There was no write protection on the disks, but you could click a slider on the floppy to prevent someone else from deleting or overwriting on it.
There were shareware cds. They hadn't figured out write protection or the concept of having a serial number that couldn't be used multiple times yet. I liked games like 7th guest and 11th hour. That and I played Lawnmower Man back in the day. Oh, yes, and Rocket Jockey, Rise of the Triad, Road Rash, I'll think of some others from back then.
This is one of those concepts like using a VCR to record a program on a cable channel because that was the only way it could be saved for posterity (or until 20 years later and the tracking was so shit it became unwatchable).