Yes, some commanders run a program that reads the logs from the harddisk and transmits it to a network. Inara among others pick up this information and let's the commanders use it. The problem of course is that if there is a very good price somewhere, the demand gets filled quickly, and Inara won't update the price listed unless some commander has visited. Your method keeps the data private and apparently updates realtime. BTW, those prices looked impressive to me, I don't often use Inara for trading but I don't think I've seen them often.
Also as many sites don't provide legacy data any longer, it's probably even more useful to know for legacy players.