Thank you for reaching out and I am happy to help!
The W3 Total Cache uses the rewrite capabilities of your server to serve the images as a webp.
All images converted with the Image Service tool are sent to a third-party server maintained by the W3 Total Cache team which reduces resource consumption and allows for a large number of conversions in environments where resources can be limited such as shared hosting. Images sent to the W3TC server for conversion are only held temporarily and no permanent information is kept on the server regarding the images.
The images are converted:
https://financebenz.com/wp-content/uploads/2023/07/Delete-Transaction-History-Featured-Image.webp

However, you cannot download images as webp. webp is a web format.

I hope this answers your questions.

Thanks!