multiple world vs. single world game structure best practices

I’m currently working on a transition system that I plan to use for a number of both SP and MP games. I have it setup to either use a single world with stream levels, or the seamless travel functions to be able to change the world at runtime. However, I’m noticing there is a bit of extra complexity and friction regarding seamless travel, as well as some limitations like not being able to change the game mode type when changing the level.

After getting this setup, it got me wondering whether it was worth the effort. Right now it seems like the best and simplest option is to have a loading screen movie at the start of the game, or when connecting to a new server, but otherwise having the entire game take place in the same world. Then I can have stream levels or use world partition and spatially break things up as appropriate to have different scenes in the game.

I’m wondering if anyone has shipped a game using seamless travel, and could comment on whether I’m on the right track here or not. Is it worth the effort to maintain this system?