Pro instant ship transfer: Convenience.
Con instant ship transfer: Gamey.
Pro timed ship transfer: Adds a realistic mechanic to a service that makes sense: Someone else will drive your ship to the destination, but it takes time you can use doing something else while it happens = multitasking!
Con timed ship transfer: Inconvenient.
At the moment I'm out at Jacques after a 5-months or so exploration trip, coming there by traversing the Long Bar from the far end. After bumbling about in the neighbourhood for a bit, I parked my Asp "Betsy" and built a T-6 miner "Bumblebee" that I now put about it in.
There is a lonely feeling out there, even if I see other CMDRs once in a while, due to the 22 kly distance to the main bubble of humanity. I sometimes long to go back there, since my Python is parked somewhere in the bubble, since I've essentially missed all of the Engineers except for the beta testing. We do have the spiffy new mission boards and such at Jacques, but alas no missions. And the shipyard and outfitting opportunities are somewhat sparse on options.
However, I would never replace that feeling of isolation with a convenient instant mechanic. Because, then the feeling would be gone. There would be nowhere with a frontier feeling. Jacques is an extreme example, but the same can be said within the bubble: If one wants to work on the outskirts of it, there should be a bit of a frontier feeling. Having to wait a little for another ship to arrive will require a minimum of planning. Which I'm willing to do despite being one if those so-called "low on time" players that only have 2-5 hours a week to play in, if that. Elite Dangerous is just not the kind of game that should be trying to cater with instant gratification mechanics.

S