Ease of use, all the effects you could ever want, routing options, amp and cab sims - it’s all there in a small convenient package.
The one downside is sometimes the interface and ideally using a computer to edit content. Individual effects with knobs for things are possibly easier to dial in - but it depends on the user.
For instance @BigRedX has a workflow for his helix that works, I struggled to make my stomp workflow rewarding