Is VPN important for streaming in fire stick?

Hello guys! Please clear my doubts regarding vpn. Is that really important to use vpn on a fire stick? I'm using thop tv,Oreo tv,etc. I'm not sure those apps legal or not? If I use those apps without vpn, will I get any trouble?

If the vpn is important, will it be streaming smoothly with the vpn on? Because I doubt it.

Thoughts?