Bigger also means they can put more sensors onboard (though you can do quite a bit with Estes). But even the Shuttle SRBs used parachute recovery, although without popping the nose cone.

Biggest difference I can think of is that the SRBs had a gimballing nozzle. From photos on the project website, it looks like fins are fixed too. I don't know the law around it, but guess adding control surfaces would make this into a guided missile!

https://www.uscrpl.com/traveler-iv http://www.uscrpl.com/updates/2019/5/22/traveler-iv