The right choice when transparency matters
If the WebP has a transparent background — a logo, an icon, a cut-out product shot — PNG is the conversion to make. JPEG would replace the transparency with a solid colour, and getting it back means cutting it out again by hand.
PNG is also lossless, so an image converted here and then edited loses nothing on each save. For a file about to go through several rounds of editing, that is worth the size.