Video codecs as used for images also have big disadvantages since they weren't designed for many picture-focused workflows
> only matters during the transitional period.
which can be decades, so this matters a lot
> it seems to massively outweigh any advantage JXL has
Since you haven't listed any other advantages outside of downplaying the compatibility during transition, so that's hard to weigh. Also, it's not like, if we're talking about the whole lifetime, hardware couldn't add support
The advantage is increased battery life and performance, which is way more important to most end users than any of the advantages I've seen for JXL. People are not pixel-peeping different images to compare quality, they are annoyed when their battery dies.
As to hardware adding support for JXL, that seems extremely unlikely: image decoding is less impactful than video decoding, and the cost of adding custom decoding silicon to a chip is very high, as is adding support to software for that hardware. Being able to piggy-back on the work already done for video meaning you get that stuff for free makes it way more viable. AV1 decoding is already out there in virtually every new device, and rolling out hardware support is very slow, it's massively ahead in that respect.
Video codecs as used for images also have big disadvantages since they weren't designed for many picture-focused workflows
> only matters during the transitional period.
which can be decades, so this matters a lot
> it seems to massively outweigh any advantage JXL has
Since you haven't listed any other advantages outside of downplaying the compatibility during transition, so that's hard to weigh. Also, it's not like, if we're talking about the whole lifetime, hardware couldn't add support