PTO's are usually used as a gateway or bridge to a more traditional short-term NHL (or AHL) contract, at least on the occasions when they are successful. Otherwise, as stated in its name, it's basically the mechanism for a try out deal, with no guarantee on the outcome for the player. Last year, the B's originally brought back Danton Heinen under a PTO, and he played well enough to eventually earn a league-minimum deal for the rest of last season, had a pretty decent year, and parlayed that into a new deal in Vancouver.
Moral of the story? You do what you gotta do to stay in The Show. OR "beggars can't be choosers" ...
From PTO to Full time, Bruins Heinen Continues to Make an Impact (thehockeywriters.com)
FWIW while it's a fun discussion here, I doubt JvR spends even a second worried about eclipsing Langway's UNH record for most games played in the NHL/WHA. The lack of All-Star appearances/selections, ditto. If anything still lights his competitive fire, it has to be the thing he sees on his kid brother's ring finger at their offseason family get-togethers. And I do agree, I don't see any reason for JvR to be winding it down with Euro hockey. His lifetime NHL earnings FAR exceed those of a career-long bottom-six grinder like Winnik, who likely continued to play after his NHL days because (1) he still loves to play; (2) he won't make more off the ice; and (3) it made sense to maximize his lifetime earnings. Guys like Jaromir Jagr or Pavel Datsyuk - who have (like JvR) made more than enough in the NHL - are rare birds who love to play, and wanted to play closer to home after retiring from the NHL.
It's always possible that JvR could catch on with someone after camp if there is a team that develops a need for what he offers. But what that is isn't as prominent in the NHL as it was only a few seasons ago. I do think his chances of playing this season AND also breaking Langway's "record" are over 50%, but it's not the slam dunk certainty it seemed to be, not so long ago. This is what a late-stage pro sports career often looks like ...