Enable an image to automatically be saved as a jpeg as the first choice

Most of the time I use Save As to create a new file with a different name. For me this is a bad idea. 

Couldn’t you just change the “Quick export as” preference default to export as jpeg and accomplish the same thing? You can assign a keyboard shortcut to the quick export (I use ctrl+alt+shift+w). Then you wouldn’t need to save Photoshop file at all since you’re losing all layers anyway.

Jpeg cannot be a general default. The jpeg file format specification has so many limitations, that basically anything you can do to a file in Photoshop will put it outside the legal jpeg specification.

• a jpeg needs to be a flat file, no layers of any kind
• it needs to be 8 bit color depth, whereas 16 bit is the general standard nowadays
• it cannot have transparency
• it cannot contain alpha channels

I can see the appeal of that. A user preference to set a default "Save As" format (such as JPEG) would be a nice time-saver for workflows where the final output is almost always the same file type.