Yes you'd think. I tried the mic into the RE's instrument input and also into the front end of the amp. Both sounded like you'd expect, very low gain, not a very solid sound. I think maybe the mic into the effects input is still low gain but adding just enough to give the pickup some extra depth. The difference is definitely there and it sounds good.
I recorded a couple quick samples. I hadn't warmed up before so excuse any ripe notes. All are recorded from the RE's DI into a Zoom livetrack L12, no effects or EQ, no boost and flat treble knob on the RE, no amp in the room. I did 2 passes on the first track with the mic into the effects return and Full Circle into the input, one with the mic just under the G side bridge foot about an inch off the top and the second with it swung out to point more at the F hole. The 2nd track is the pickup alone.
I hear much more mic in the recorded DI sound than I do when coming from the RE's 1/4" out to the amp. The difference when adding the mic is more subtle through the amp. Also the pickup alone sounds much more smooth and natural through the amp. The DI sound of the pickup is not good IMO. I have used the DI live though and it sounded good from what I remember. I have 3 gigs this week and I'm gonna try adding the mic.