Each JMAP server should include IMAP QRESYNC like functionality at least. Plus the ability to batch JMAP calls.
For instance, if you have five folders with IMAP, it might take at least five hops to access them.
With JMAP, it could be accomplished in just one call, returning the location of each new email in each folder.
This really benefits when you first connect a client to a server that has to sync all the mail locally, and partially each time the client starts that has to check all the folders for new messages. But realistically when a client is opened (that is when you turn on the computer till you turn it off, if you turn it off and don't put it to sleep). Also most people has only a few folders, say less than 10.
