And how exactly does this feature make browsing safer?

Um, so? The question was "[in which way does] Chrome has better security?" Not "Can anyone name a random Chrome feature?"

Firefox's Sync appears to be just as secure if not more secure (there's no option to NOT have end to end encryption): https://hacks.mozilla.org/2018/11/firefox-sync-privacy/

I think sync is a pretty niche feature anyway.

Doesn't Firefox do the same? IIRC Firefox encrypts your data client side and it doesn't get decrypted on their servers.