Tab sync is not about having the stuff you see on one browser show up on the other, but about being able to bring up the tabs from another device.
Delicious to my knowledge does not fix that because (unless something has changed) it depends on you actively bookmarking something.
Typical use case: I have to run out of the office, and suddenly remember I need the address to that place I was looking at. Tap the tab symbol, and find the tab from my office desktop, and I have it without having to search.
I agree with you it'd be nice to add an account that is separate from all my other stuff, but tab syncing is one of those features that you'll likely not use much, but when you happen to want it, it can be immensely useful.
Delicious to my knowledge does not fix that because (unless something has changed) it depends on you actively bookmarking something.
Typical use case: I have to run out of the office, and suddenly remember I need the address to that place I was looking at. Tap the tab symbol, and find the tab from my office desktop, and I have it without having to search.
I agree with you it'd be nice to add an account that is separate from all my other stuff, but tab syncing is one of those features that you'll likely not use much, but when you happen to want it, it can be immensely useful.