Here are three benefits of applying to a school that uses rolling admissions: https://insights.collegeconfidential.com/rolling-admission
Applying early to rolling admission schools may also be exempt from REA or SCEA restrictions against other early applications (check the REA or SCEA school to see if this is true for that school).
Being accepted to one of her top 2 schools, and a safety, by mid-October was tremendously beneficial to my D17. It made the entire process much less stressful.
I think it also helped her impression of the school - she ended up there.