Making the sensor smaller and cheaper also enables larger sensors at the equivalent cost and form factor of a current sensor though, which would change photos (if you think higher output resolution is a change to an image). The benefit doesn't have to be taken as making things cheaper.
Full-frame at APS-C prices would be great. It would lose one of the perks of APS-C: crop factor. Getting 450mm out of a 70-300mm lens is nice.
edit: since it's apparently not clear and I'm getting downvoted for sharing how this benefits a harmless personal preference, I will emphasize that I'm speaking to my needs. The 70-300 lens is what I use, not some abstract construct meant to represent all purposes.
The crop factor is generally a perk for people who shoot at the ranges I shoot at even if it comes with compromises for other needs.
Crop factor is only an advantage for APS-C cameras where the pixel density is higher than the comparable FF camera. That's not always true, eg I have a Sony a7Riv, which has 26MP in crop mode (more than APS-C cameras).
The "croppability" of the image is not really a function of the sensor size, it's a function of pixel density. APS-C cameras used to have higher pixel density than FF cameras, but that hasn't been universally true recently.
