I am sure this sounds harsh, but if you are looking for arguments to have a pump, you don't need one.
Are you struggling to manage your diabetes with injections in any way? Do you need the ability to adapt your basal throughout the day? Do you need smaller bolus doses? Have you done any research into the benefits of having a pump and considered how that would improve your life? Have you review the NICE guidelines for a pump?
Like many, I was required to go on a course (the local equivalent of DAFNE) but this was to ensure I was carb counting and, I suspect, for the DSN who was taking the course to assess whether I would be able to manage the added complexities that come with a pump and that MDI was second nature to me so I could calmly revert back under the stressful situation when the pump fails.
Remember, a pump is an expensive piece of kit and the NHS has limited funds so, unfortunately, they need to limit the number of people that it is available to.
Also bear in mind that different pumps are available at different clinics. Omnipod is not an option at my clinic, for example, and I had to make a very strong case to go off piste away from the standard Medtronic they offered to everyone else.