When connecting to the servers for the first time, addons are automatically downloaded from Steam Workshop, but they are not considered signed
The server checks the subscriptions every time the player connects (quickly), and if it does not find them, it looks for the player in the /workshop/ folder (slower)
If you don't want to wait for the server to check for an addon in your /workshop/ folder - just subscribe to the entire list of addons and the connection will be much faster