The detail you might miss on first glance is that you don't also convert bonuses of the weapon you play to . So if you whip out a Old Shotgun, you must use your on that attack, ignoring the +3 . That makes it somewhat negative/neutral on most rogues trying to compensate for their poor combat score.
However, an "add " type weapon like Hatchet would double it up, mainly relevant on Kymani Jones and Wendy Adams. The only other one I can think of is Butterfly Swords's second attack, which is only maybe relevant for "Skids" O'Toole.
Probably the main utility here is the effectively 0-cost bonus action to get a weapon out even when you're already engaged. That's pretty mid until if you have some parley interaction like Alessandra Zorzi and/or Eldritch Tongue.