Having bought the 10-trip ticket in Belgium, I can tell you that it won't produce cash-savings for incredibly short journeys like Bruges-Gent. (You don't sound like you can use all ten of them anyway, even though they can be shared among multiple persons.)
If you were closer to using all the lines on the card, there is one advantage of the pass that would be worth money for certain travelers, which is the ability to avoid waiting in line to buy single-journey tickets. American credit cards (NOT talking about chip and pin or physical technology) don't work in Belgian station ticket machines. So you might have to wait in a long line for a human agent to buy the ticket, and miss the train you had hoped to be on.
There is another peculiar value to the 10-trip, which is that on some daytrip days (yes, that's how easy it is to daytrip in Belgium) I would write in a destination I hoped to go to that was beyond another destination of value. Then, if it started to rain, or the trains were late, I might settle for the closer place that day.
There is a faint nostalgia in the OP for Railpass products, which are fading in popularity and value. They were never that good for short trips in one day, and tricky for multiple countries in the same day. In fact, I DID use a 10-trip ticket to go from Antwerp to Lille, France (on local trains, two changes ... ) by buying an international round-trip from Mouscron, Belgium to Lille, France. Mouscron is the last Belgian station before the border, so it is where any domestic pass product would cease to work.
Have you made plans for your luggage while in Gent? Gent is so close that you could go there and back from Bruges, which can be seen in one day. It is a challenge to see Gent and Brussels in one day ... Pay attention to which Brussels station your train to Paris leaves from. You get a free transfer from the other two downtown stations (on the railroad, not the Metro) but you need a few minutes to do that.
