I've noticed that most of the people use the advanced cargo scanner vs. the disco scanner. I get that it's very useful to see what kinda ID and equipment etc the other chap is carrying as fast as possible.
However, my question is about escorting. If I'm escorting traders, won't it be better to have discovery scanner so that they show up on my radar earlier and I can warn the traders I'm escorting? Or is the difference to small to worry about?
Ships show at 15 clicks on your HUD bottom left anyways, and at 10 clicks you can F9 them to see what they're flying.
With the Adv. Cargo scanner you've a greater range to actually scan their gear then.
The only other slight advantage that discovery scanner has is that in clouds/nebulas where your scan range is reduced, you can see jump holes etc on your hud further away if you use the discovery scanner. But of course they should appear on your map anyways.