Drop a TIFF above, get a PNG back with every pixel exactly as the scanner recorded it.
Nothing is given up on the way across. PNG compresses losslessly: it finds patterns and stores them compactly rather than discarding detail. Decode the result and you get back precisely the values the TIFF held, which matters when the scan is evidence, artwork or something you will edit later.
Where TIFFs come from: flatbed scanners, fax gateways, archives, laboratory and medical equipment. All of them chose the format for the same reason - it keeps everything - and none of them considered that browsers never would.
If both formats are lossless, what is the conversion for? Support. PNG opens in every browser, editor, phone and upload form; TIFF opens in specialist software and Windows Photos. The picture itself is unchanged, and only the container around it is different.
Size: uncompressed TIFFs commonly run 20 to 50MB for a single page, and PNG usually takes a good deal off that. The same image as PNG usually lands between a fifth and a half of that, and a scan of text with large white areas can fall further still.
If size matters more than fidelity, TIFF to JPG goes much smaller by discarding detail. For a document rather than a picture, TIFF to PDF keeps all the pages.
Only the first page of a multi-page TIFF is converted here, and batches run at once.