Yes, every user will need to generate an offline request file because the licenses are "hardware-locked". This means that the product key is directly associated with a particular computer. But you can automate this so it's not a big deal. For instance, you can integrate into your app a way to generate the offline activation request remotely.
So a user can generate the offline activation requests remotely, then submit these files to your website (your website will use limelm.pkey.manualActivation), and lastly send the activation responses back to the computer.
Does that make sense?