I think that if it's possible, it's best to use dialogs. That's easiest for people to learn.. instead of 10000 commands. but for things like specifying a certain number like in my banking system, it's best to have a command.
Things like settings is best for a dialog..
if you try, open wh40ktd change ur name to 40k_ralle89 and try pressing ESC you'll see my admin system which only can a few things but it works.
I also have those abilities in my map, an ability with no function but a releases a trigger. these are good for massing stuff like -buylife which would be hard to write 20 times, then it's easy to just use an ability each time or have a command like -buylife 100
Just my oppinions