There are many situations where you want to use JIRA Service Desk on the go.
There are different scenarios from the customer and support site so you will need both a mobile optimised service desk and a native mobile app.

The existing JIRA mobile interface doesn't capture all the needs. It's also a different user experience if you compare it with service desk.

As a customer i want:

• Track the progress of my issues
• Create new requests
• Comment on my issues
• Upload a photo of a defect
• Search the knowledge base

As a support agent i want:

• Don't print the issue to have all details of the issue with me
• Change the status of the issue on the go (workflow)
• Create new requests or sub tasks
• Upload a photo of a defect
• Search the knowledge base
• Able to add request participant
• Able to add comment internally or share with customer
• Able to set the Request Type field

That are only a few of my thoughts.

The JIRA mobile interface is actually really basic for service desk users.
I know there are many JIRA apps on the App Store but an official app from Atlassian for JIRA Service Desk Customers would be good deal.