Hardware acceleration seems to be blocked on certain systems (e.g. "Blocklisted by gfxInfo" and "Blocklisted; failure code FEATURE_HARDWARE_VIDEO_DECODING_NO_LINUX_NVIDIA" under "HARDWARE_VIDEO_DECODING" in about:support; this is on Linux under Wayland with an NVIDIA GPU). An option in about:config to ignore the blocklist (similar to Chromium-based browsers' "ignore-gpu-blocklist" flag) would make using hardware acceleration easier and make loading graphics-intensive pages faster.
