No, the 10x50 SV is way different than a 10x42. I have had many 10x42's and honestly I never cared for any of them that much. I had trouble holding them steady and they always seemed a little finicky ,as far as, eye placement. The bigger exit pupil on the 10x50 makes a huge difference in easy eye placement and comfort. Of course the 50mm is better in low light than a 42mm. Where the 10x50 SV shines is in the balance of the binocular. It doesn't FEEL like a 50mm when you use it. It feels more like a 42mm in weight. The big thing that makes it so outstanding is the AFOV. It is HUGE for a 10x50. So you have this extremely detailed close up 10x view with a BIG FOV on top of it and edges that are sharp right to the field stop. The result is this amazing immersive field of view that is right on top of the bird. It is a WOW binocular if there ever was one.I agree with you about anyone using a 10x50 as their everyday main binocular.
They are nice to look through, but too big and heavy and the performance of a
quality 10x42 is much the same.
That is why 42mm binoculars are the biggest seller.
Jerry