Hot spots are areas where the flame hits the pot bottom and the heat is not evenly distributed. If you are just boiling water, this is of no consequence, but if you are actually cooking in it, the food the will burn--- and stick --- at the hot spot.
Typically, the thinner the material, the more this will happen. Titanium transfers heat differently than aluminum anyway, and then is manufactured thinner because it is stronger and it is being used in applications where weight is a primary criterion.
On the other hand, the bowl shape is better for real cooking than the square-shouldered pots used for boilers-- the round bottom edge makes easier to stir and mix in. It is easier to eat from for the same reason.
The lighter butane stoves tend to be little blowtorches with a small very hot flame pattern, adding to the hot spot problem. Again, if you are just boiling water, it isn't a food quality issue, but it makes it harder to simmer or cook something like scrambled eggs.