You would need to shoot a lot of ammo to make reloading economic in a reasonable timescale, but there are other reasons for reloading:
1) As you say it is interesting and many happy hours can be had fiddling around with dies, powders, bullets, primers, crimps case length/headspace etc.
2) Many guns perform much better when using a home load which suits them rather than factory ammunition, but you might have to put in quite a bit of time to find the load which works best in your gun.
I reload for both of the above reasons