Not really, lossless WEBP still decodes much faster than lossless JXL, so if you need to decode the images faster, you use WEBP. Yes, you could also speculatively decode the JXL images to hide the decode time.

For lossy, neither is in a good place, since lossy AVIF beats both lossy JXL and lossy WEBP. Lossless AVIF is a joke and barely competes with PNG.