What is WEBP?
WebP is Google's image format for the web, and the rare one that does both jobs: lossy compression that beats JPEG at the same quality, lossless compression that beats PNG, and an alpha channel either way. Every current browser reads it; older software often still does not.
What is TIFF?
TIFF is the archival and print format - lossless, high bit depth, and flexible enough to hold multiple pages in one file. Scanners, publishing workflows and document archives lean on it heavily. Browsers have never displayed it, which is why it is offered here as a target rather than a source.