Congratulations. I have never seen a dispenser for these before, portable or not. I just have a clunky tool box for them, and no organization except the bags they came in.
As an amateur for many years, my most common use of zip ties has been working on boats, cars and other low voltage electrical. On boats they are very useful because there is a lot of rewiring, and there is often a purpose for the kind that have holes for screws.
It is true that the white ones will last only a short time exposed to sunlight. Black ones can deteriorate too but last longer.
I have all the different "guns" for tightening and cutting. They work but I find them to be more gadgets than useful.
Colored ones are good for marking things like luggage.
I have just picked ties up wherever, and have found the T&B and Panduit to be very good.