Without the experience actually playing Traveller but having played around with the system I'd say one thing that will "hook" some players is when they create the characters background story based on events and do the same with allies they roll up.
I was just recently creating a background NPC for my hypothetical players to encounter as a owner/operator of a one man trading ship and it is a perfect example.
He and his allies (I planned none but the dice said otherwise) have a much more complex and full background than I originally envisioned, even if he didn't have great ability scores I'd love playing him for the back ground. The same for his allies as far as I've gone at creating them. A female Agent (corporate), a female Merchant Academy graduate and broker (for the same company as the original character) and a Doctor (based on a Hospital ship beyond the Imperial borders). All with reasons why they are close to him. His story became such that I added his former Captain as a contact even though that never rolled, it was just NEEDED by the background. The 2 women were allies of each other and the doctor an ally of the Broker as well, making a tight knit group. Each has REASONS to be allies with the others (not the agent and doctor so far but I haven't completed rolling them up and as yet they aren't allies just acquaintances helping save the life of the Broker/lover of the central character (Jack Solo). Even that character name Jack Solo ended becoming a name change after he retired to avoid the notoriety he gained in saving his lover and become allies of the doctor and abandoned his original name that I had to create, changing the planned background one again.
There is so much more to this character than I planned and if players did the same when creating their own and interlinking them it could easily make them much more attached to even a character they would normally reject as "too wimpy" just for the background.