Level streaming vs non-streaming

Hello,

Pretty much as the title says. Pros cons.

I was wondering if streaming could be considered a replacement for non-streaming or if there are still reasons to use non-streaming.
Maybe some performance implications or other reasons for not using streaming?

NOTE: I forgot to mention seamless and non-seamless travel

You can us both. Loading new non streamed level is good for engine clenaups and easier to manage.