About Server side method

hello.

While looking at the environment settings, I happened to see a feature called server side with w3 total cache.

Since I am using w3 total cache, I read the documentation and completed the setup.

But I have a few questions.

1) If I set the dynamic block to server side with w3 total cache in the settings, do I have to use server side detection for the detection that can be set in the ad block?

2) Is the server side better than the client side?

Thank you.