Isn't that kind of the point though? AV1/AVIF has an extremely strong case for hardware implementations: you need efficient (both in terms of processing and compression) video decoding on modern devices because the battery cost/bandwidth cost is so high otherwise.
Image decoding is nice to have, but less important. When you are deciding to put custom hardware into a device, that's a huge investment in something only useful for that one task. Being compatible with a video format so you can share that hardware between the two tasks is a huge win for hardware manufacturers who get two-for-one, and for the rate of adoption.
With AV1 already very efficient and rolled out in a lot of hardware already, it just has a huge advantage.
Image decoding is nice to have, but less important. When you are deciding to put custom hardware into a device, that's a huge investment in something only useful for that one task. Being compatible with a video format so you can share that hardware between the two tasks is a huge win for hardware manufacturers who get two-for-one, and for the rate of adoption.
With AV1 already very efficient and rolled out in a lot of hardware already, it just has a huge advantage.