Yeah, Rogue Traders and retinues are all about pomp, and remembrance; they want, along with everything, to literally write their name in the stars, for everyone to read, and even after they are long dead, and their successors have either raised their place in the scheme of things to even higher planes, or screwed up, and burned it all down, to be THE member of their Dynasty remembered. Winterscale's Realm has grown vast, and many have borne the Warrant, but Sebastian Winterscale is still the one remembered.
To the point, a signature piece of gear can help to remind people who they are. Marneus Calgar might be a great and powerful Astartes, Chapter Master of the Ultramarines, and a riveting tactician, but I, at least, always first remember the dual powerfists. One of my RT story characters, Aedan Qel-Drake, is famous for carrying an inferno pistol; he actually almost never uses it; why would he need to, most of the time, where he goes, but such a rare, iconic item is easily recalled, and can be hard to duplicate, should someone want to impersonate Qel-Drake. Like the Dragon's Ire, such a set of dueling pistols, or some similar item, might be handed down as an emblem, to the next Trader, sort of as proof, like an Inquisitor's rosette. It's actual use can be minor; in a game of D&D I played, my character was the heir to a throne, and the proof was a broken sword he carried. It certainly wasn't usable, and wasn't repairable, either, but it was a sign that he was who he claimed to be.