Sometimes you win, sometimes you lose. I think to understand how gem recruit is good and bad really requires you to give it a shot and have your own experiences.
Dragon Era - Boop - an80e3 - "Get on with the job"
For new player Gem Recruit is good thing. You should consider it around levels 50-60, when you have enough Command Points to use this 6* cards. Don't forget that good cards use 18-20 CP each.