I wouldn't want to keep any singular prospect up for the entire year, but having the spot open so that you can rotate any one of those prospects so they can get, I dunno, 10-15 games then cycle the next guy in would be worthwhile.
Cycling would be hard to do because you would have to bank on the fact that someone would be hot or producing enough at each point of turnover to be worthy of inheriting the spot. What happens if you get, say, halfway into the season and all the guys who haven't had their audition time yet are in massive funks and are in no way prepared for an NHL call-up?
Plus it's also likely better for guys to get seasons with consistency in them, where they know where they'll play and that if they go up it's because they've earned it and not because their turn came around irrespective of how they're performing. Plus it would suck to call someone up who's playing well and making strides, they flounder at the NHL level, and then they go back down dejected and out of sorts and can't recapture the groove they were on beforehand.
If someone force's the team's hand in camp, great we'll cross that bridge when we get there. And reasonably it's not like there are enough indispensable players on the roster that you couldn't punt one, or even two to make room for, say, Musty if he looks like a worldbeater and Gushchin if he's clicking. It might suck, but thanks for your service Kostin, or Dellandrea, or Grunstrom, or Afanasyev. Maybe you find some contender that wants Sturm to anchor their 4th line for a mid-round pick or lottery ticket prospect. Maybe you find Goodrow a home mid-season with a team that's willing to shoulder that cap hit when it's pro-rated for the rest of the year and can be readdressed in teh off-season. Having to fit people in because you've got too many worthwhile NHL bodies is a nice problem to have. I hardly think the team is in a spot where they're going to see someone legitimately deserving of NHL ice time and go "yeah, but if I do that then what of Luke Kunin?"
To be clear: I also don't expect this scenario to play out. Smith makes the roster for sure. Celebrini does if he signs. It would take one of the others playing absolutely out of their minds to force management's hand. Like Musty would have to be PPG and absolutely bodying people in the pre-season for him to get anything more than the cursory 9-game contract-sliding audition. Gushchin or Bordeleau or Graf would have to show they are clearly better than whatever other bottom 6 options are fighting with them, at which point why wouldn't you take the better performer. And other than that I don't really see many guys who threaten NHL playing time at this juncture. Not unless you think Dickinson waltzes into camp and is peak Pietrangelo right now.