WEBP usually wins on delivery efficiency

When the goal is lower page weight for modern visitors, WEBP is often the stronger default. It generally gives a better balance between compression and acceptable visual quality.

JPG still wins in many operational environments

Many legacy tools, upload validators and partner workflows still expect JPG. That means teams often need conversion even when WEBP is the preferred delivery format on the public site.

Practical recommendation

Store or receive the source in whatever format your workflow supports best, then convert outward for the channel that needs it. That avoids unnecessary debates around one universal format.