Solar Panels Pools California

Turning off the pool’s solar heater during winter months?
When the solar guy installed our panels, he advised us to turn off the solar during winter months.
Our neighbor has a pool and solar heating and does NOT turn off his.
We’re in California, so there’s not a danger of freezing… the water drains from the roof panels when there’s no sun anyways, sooo??? We’re wondering why and if we really have to shut them down for winter.
I wonder why also. I lived in So Calif and used my spa all year round.
Maybe to drain it? Maybe to cause it to need service more often? (There’s my suspicion showing.)
Second thought: I did fint a layer of ice in my bird bath a coupe winter mornings.
Aqua Gunite, Inc. Bay Area Swimming Pool Remodeling