Migrating SQL Server databases
Basically yes, all you'd need is to backup and restore the databases. However, there's a bunch of stuff that won't do.


Server level settings (MAXDOP/CTFP, etc.)
Agent Jobs
Maintenance plans   
Linked Servers   
Users/Logins 
Any other customization


It's kind of a pain in the butt to find all this stuff, and even if it's a one time move, scripting it all out can be a hassle. I'd recommend something like the free dba tools to help you with that.