The benefit of this camera is the size. It was a critical mirrorless market, and Canon has done quite remarkably well with it. It is about 10 percent wider than the SL-2, 10 percent shorter, and about 10 percent heavier than that older crop form factor. And that SL line is awesome for certain applications. I own two of them that I use to plant in various places as remotes, often out in the woods on infra red triggers. (Aside from the tilty flippy screen, the SL1 is pretty much as good as the SL2, being one of the "lateralgrades" Canon has done in the past couple of years.)
The sensor they put in it is a whole lot better than the crop one in the SLR. And, yes, the 6D2 did not push the performance envelope much at all past the then-ancient 6D1. And, yes, the 6D1 selling proposition of a 5-series-class sensor in a cheap body was pretty much shot with the 6D2. And yes, Canon will take that 6D2 sensor and - in writing - claim it is "all new" several times over, which will be as true as it was back when we recycled 18mp sensors for a generation. But none of that signifies, because the RP is all about the size. If you don't need it, you don't need it.
As soon as Canon releases a >40mp camera with >7 fps in servo, I'll buy that, and pick up one of these used (unfortunately, I think there will be time to build a used market).