~$180 to repair with AC ($99 AC + $79 fee) versus ~$500 without AC.
Unless you think you have greater than 24% probability of damaging it in 2 years (more than cosmetically, which they will refuse to repair), you are better off going without AC.
99/(499-79) = 0.24
I thought this was supposed to be a rugged watch?
Biggest risk is probably losing it, for which you are definitely better going without AC, as they will laugh at you when you try and claim for a lost watch.
My experience with batteries on Apple Watches is the battery health goes down to a little above 80% and stubbornly stays there, which they will refuse to replace.