I think we really wanted Lance show he could handle the #2.
In that situation, you can develop a few packages for him that are primarily RPO. The running QB skills are very good and it lets you take some of that off Dak.
But if he can't beat out Cooper Rush with a full TC and pre-season, well, it isn't looking good.
I still don't have any problem with the trade. We gave up a 4th for a guy who the 49ers invested three first in. That's a decent price for a look see on someone who was very highly regarded coming out of college.