If you use Cloudflare you can just use their origin server certificate in nginx. I have one that expires in 2038. This way you do not have to worry about whether the renewals every three months work out etc.
Cdn is very in important in today's Web apps.
I do not know why someone wouldn't need it if their program fully support it.
The benefits of cloudflare are just too good to overlook.
Also, why did you move from litespeed to ngix? Litespeed & their cache performs better Nginx/varnish etc.