I can see why folk choose to drink instant coffee, but the only reason I can see is that it is less hassle to prepare, which is a sad argument. Deciding to drink instant coffee because it is easy to make would be like choosing to sleep on the floor because it's less effort than making the bed.
But it is undeniable that preparing real coffee can require more apparatus, so for the last year or so I've been making up a nice big brew first thing in the morning and taking a big flask to work. This plan had a few drawbacks; most notably the requirement to have a heavy flask in my rucksack when cycling to work, and the sad fact that I'd run out of coffee before properly waking up (around 11am). My morning routine is timed down to the nearest minute so sitting around making coffee was sometimes unhelpful in my efforts to get to work on time.
So I wanted proper coffee at work, but I didn't want to have to wash up a cone filter, cafetiere or one of those neato combined reusable filter cups. I also needed a system that would neatly deal with the problem of disposing of coffee grounds without filling the canteen bin with black liquid.