This is exactly why I loved my tanks back in the day, all the critters you find.Before getting back into the hobby about 1year ago ( yes my new tank was started with live rock), I had a reef tank for approximately 16 years that was started in the mid 1990s. All we used was live rock. There weren’t frag plugs and every coral purchased came on a new piece of live rock. When the lights went out the flashlight would come out so I could see all the hitch hikers. It was as fascinating and interesting as watching my tank with the lights on. I never had an unwanted hitch hiker. I wouldn’t set up a tank with anything but live rock.
Just getting back into the hobby after years and years break. I would totally go live rock, but I can't find any except for rock that's been in peoples tanks or Florida live rock. The Florida live rock just doesn't look good to me and I'd wager the life on the rock isn't nearly as good as the stuff we got from the Pacific.