Gasket/seal fell off sun roof?

I closed my sunroof and a gasket fell off from the inside. It doesn’t appear to need glue to be placed on.

My question is, is it hard to put back on and also is it hazardous? (Such as water getting in)?

Do I even need it?

Here’s a quick video, 04 Kia amanti https://imgur.com/a/HajDA66

Ps: the gasket fell from the inside of the sunroof not out. And it fell from where it opens from.

This gaskets slide into a channel to secure it.

Is it relatively easy to put bak on?

Why would the manufacturer bother to install it if it wasn’t necessary?

Is it difficult to put on

@COROLLAGUY1 I can’t for the life of me figure out how to install it. Let alone have any leverage to fit my hands. Is there a diagram for this specific piece?

If you go to an auto body shop, they will be able to install it in a couple of minutes–assuming that it isn’t damaged.