I was just messing around with my clubhead gauge and my Cobra F7 and Titleist 915D2. First comment is that since the soles are convex, the clubs do not necessarily have a natural, square sitting position with the shaft in playing position. By natural, I mean that the club just sits naturally into the desired orientation. I've seen this with all 460cc heads, but it's more intentional now. Tom Wishon has mentioned this in his discourses on adjustable heads.
In fact, many of the ones I've measured will have a most stable/natural sitting position with the shaft leaning rearwards. Or a quite open clubface if you hold the shaft straight (90 degrees from the ground). That is due to the overall sole shape being less convex and somewhat flatter towards the rear of the head.
So for those who, like me, think we sole the club and grip it how it wants to sit, we can't really keep doing that. Not effectively. And now I see that I have not been doing it. At some point I unconsciously converted to gripping the driver above the ground, verifying the face orientation, and so on.
On the Titleist, the adapter does produce quite a change in loft. The Cobra does not seem to change as much, even though they both are listed as going +/- 1.5 degrees. I'm measuring the loft at right angles to the faces, with the shaft clamped in place at right angle to the "ground" (the plate of the gauge).
Where I'm at with this is that while the adjustments can be done to change the face angle, the user still has to manipulate the way the club is held, because the driver probably won't naturally sit in the desired orientation anyway. So any face angle change is ultimately up to the golfer. Given that, if the golfer learns to hold the face the way they want it, then there is indeed a loft change.
I can't help but think that the hosel/ face angle change might still have some influence on the side spin, but that is just me wondering out loud. I wouldn't bet on it anyway.