do you need a spare? no
should you get one? depends....
I've been RVing for 24 years and used my spare twice. Glad I had it on hand. Once was July 4 th in the afternoon and I have this "not available" XRV size. Other time was nail found at departure tire pressure check. quick change and on my way.
if you have a spare, do have an ERS that will change it for you
if you don't have a spare, do have an ERS that will find one for you and be prepared to "possibly" wait longer and pay more....possibly
is there a right or wrong answer? no (unless you didn't get ERS!!!):B