Can you wait and buy it when you arrive? NO
A small tube of super glue can have so many uses during a long trip - from reparing broken shoes through to 'stitching' injuries whilst on the way to hospital!
Tubes of glue are small and weigh next to nothing so although ideal to carry in a ruck sack they are also prone to getting lost. For that reason I keep mine in the First Aid kit; that way I know where to find it in an emergency, and the emergency happens to be a medical one, the glue is found with the rest of the kit.
Much of Uganda operates on a 'make do and mend' economy where you fix what you've got rather than throw it away and buy a new one. This is reflected in the availability of items - you are unlikely to find a new strap for your camera, a new pair of Trainers or a new razor in rural Uganda, so you need to be able to repair what you already have. Super glue, because it sticks to most surfaces, and sticks well, is the most useful glue to carry.
Its famous ability to stick your fingers together can be put to good use too if you suffer a bad cut that needs stitches but you are hours or days from medical assistance. A little glue dabbed along a cut will hold the edges of a wound together until you reach professional help, but don't seal the entire wound. Always leave gaps for it to weep. It can be looked upon as a drastic cure, but a lot less likely to do harm than an attempt to stitching yourself up, and climbers have been using it this way for years!
Warning; Do make sure you keep it somewhere where the tube will not get crushed or popped - a rucksack with everything welded into one solid lump is not goood news!