If it has better hardware decode support, why are there complaints in another thread that a folder full of avifs would slow a computer to a crawl? I'd expect hardware-accelerated decoding to be smooth and efficient.
Hardware acceleration requires your device to have the requisite hardware support. Unlike AVC or HEVC, hardware support for AV1 has been quite limited and only recently has seen a slow uptick (for example, Intel CPUs now offer AV1 hardware decoding). Not sure if Apple supports it yet though. But yeah, if it requires special hardware support to be "smooth", in my mind, it is clearly inferior to its competitor codecs that work fine with software decoding (i.e. running on the CPU).