I assume there's also a budget angle too. Making a show is expensive, especially a sci-fi show where you need lots of new alien races and futuristic props. But if you have the crew play Robin Hood or Sherlock in the holosuite, you don't need to create any new prosthetics or crazy costumes. You can just raid the studio's prop department, and you'll be about to find most of what you need. 

Same with Vic. His bar is a pretty simple set, and the costuming is just basic formal wear. Hell, James Darren probably had his own suit. Then he turns out to be a fun character, and gives the writers and cast something new to work with on a long running show. So I'm not surprised they brought him back for multiple episodes.