How long until I see data?

Usually a few days after verifying. Reports fill in more over the following weeks.

You already set this up at launch. Do I still need to?

It's still worth it. Verifying under your own Google account means the data is always yours, in your name. If you'd rather, I can add you as an owner of the property I set up instead. Just ask.

Is this the same as Google Analytics?

No. Search Console shows how people find you on Google. Google Analytics shows what visitors do once they're on your site. You can connect Analytics later in your dashboard under Marketing Integrations if you want it.