How much does teaser page helps pre launch?

It’s very helpful. All your teaser page followers will get notified about your launch on the launch day.

I think this is one of the things that just needs to be done , it doesn't take much time anyway.

I will need one because it helps at building anticipation amongst your followers on social media! It helps you capture your first early users! It helps at building a waitlist as well!

It could be a better use of time if it is a standalone effort for pre-launch. As a part of extensive pre-launch effort, it is a must.