I have only rarely used a drafted citizen to disband for this purpose. I usually use outdated military units hanging on from a previous age. Most recently I used my UU (Siraphi or something? an 8.3.3 calvary) which I had a bunch of but were of little use vs Mech Infantry.
Since they could not be upgraded, they served their final duty very well and on the front, allowed city after city to build temples and courthouses. Since I usually play Democracy and all wars that I cause are over in 10 turns, I like to hold on tight to cities I have just recently "liberated". Disbanding one unit then buying the improvement works a treat.
Also for the times when you need to form a strong beachhead on a nearby continent. If I have a city on another continent or island close to the enemy continent, then I will "culture shock" a space on their island by disbanding a unit then buying a temple & cathedral. Then I place my own city and in three turns build an airport, temple and barracks.