So for my personal projects, I use lets encrypt. As far as I know (and I could be wrong now, haven't checked in a while) - their certs are only good for 3 months. Which is simple enough to get around - run a script on your box that updates the cert every 90 days automatically.
At work, we use a paid certificate that is good for a longer period of time (normally a year). So that's one benefit to paying, I suppose.
As far as encryption technologies and security, the traffic encrypted by a lets encrypt cert is just as secure as the traffic secured by a paid-for CA signed cert.
The fact that Let's Encrypt certificates expire quickly is a feature, not anything to do with paid vs. non-paid.
Let's Encrypt could have just as easily generated certificates good for a year or more. But the point of Let's Encrypt is to force you to do this in an automated way, using scripts like you suggest.
You're not getting around anything. The choice was by design.
At work, we use a paid certificate that is good for a longer period of time (normally a year). So that's one benefit to paying, I suppose.
As far as encryption technologies and security, the traffic encrypted by a lets encrypt cert is just as secure as the traffic secured by a paid-for CA signed cert.