Above post, essentially. The ability to leave the data center temporarily allows you to return to it some of the time. The inability to leave the data center temporarily can mean you need to leave it forever.

So you can do things on the other data centers such as statics or what the data center doesn't have the activity for yet.

There are those who will always queue on the data center itself such as newer players and slowly build up the activity so that people stop traveling off-world to get duty pops.