Yes thats an App Access Token Getting OAuth Access Tokens | Twitch Developers
This token can be used to make requests to the Helix API
But EventSub only uses an App Access Token to create subscriptions. Theoretically you could generate and forget about the user token.
You need to have had the streamer grant (scoped) access between their account and the ClientID.
Twitch uses the App Access Token to see if the user has connected the app with the relevant permissions.
In stead of checking if the token has the required permissions.
It can make things a little easier when you only have to back and forth with one token for all streamers connected to your app, for event sub puproses.