As i have heard a few times, connecting to an open wifi of any cafeteria or hotel is risk worthy and it can lead to data theft.

So i have two questions -

1) I joined a library recently, they are providing wifi service with it. To access the wifi a password was given to me after i paid the amount for joining the Library. Is it safe to connect to it? If yes then what's the difference between this connection and the open wifi ones?

2) At my flat, all my roommates are connected to the safe wifi. How much of my personal browsing info can someone else access through the same wifi access/router by using their laptops. (In a scenario where they don't have hacking softwares involved).