If you’re on a budget, consider this: the watch costs $100 more and it’s another (let’s say) $15/mo. That’s $280 the first year and $180 the second.
By the end of the second year you’ll have paid enough to buy a new Series 6 including AppleCare. I’d get the cell model if I really needed it, but I don’t. I’d rather have a new watch when the time comes.
If you need it or money is no object and it’s just a question of convenience, go for it!