i believe that overall a UTH is far cheaper and easier to have than a heat lamp. i know this from experience. Heat lamp bulbs cost $8-12 a bulb. plus you have to buy a ceramic fixture for each one. sometimes you can find the bulbs cheaper, but they dont last long.
for comparison...my turtle's tank has a basking heat bulb, a red heat bulb and a UVB flourescent bulb. during the day, i run the basking bulb and UVB. at night i run the red heat bulb. because they are active during the day and they need overhead heat they have lamps for day and night. turtles do bask whereas my corn doesnt. he's nocturnal. and the turtles have 3-5 inches of substrate to burrow in. so it would be pointless for me to set up a UTH for them as the heat wouldnt penetrate the 3-5 inches of thick heavy peat moss and mulch. and their substrate has to remain moist. the UTH would probably dry it out.
their basking bulb blows about every 60 days. i have to go to the store and buy them a new $8 100W bulb every 2 months. whereas for my snake's tanks, i bought them a UTH for $20 and it will probably last a very long time. also think about your power bill...since i've had the turtles set up, their bulbs use more power than the UTHs.
now in the winter time i do use a red bulb for the corn tank to keep the temps warm. but the rest of the year, i just have the UTH on. it's much easier than having to mess with blown bulbs and hot lamp fixtures. i even shelled out $50 for a combo hood fixture for my turtles tank to make handling the bulbs easier and safer. it holds all 3 bulbs and each one has it's own on/off switch.
and there's also the risk of fire with lamps. and if you're not careful, they can melt the plastic frame of screen tops. and the plastic rim of glass tanks. and if the cord gets pulled on, the fixture could fall and cause a fire.
i love my turtles, but my corn's tank is by far easier to maintain. and i wish i could just set my turtle's up with a UTH but their needs wouldnt be met.
some snakes, like ball pythons and aboreal snakes, would benefit from a daytime heat lamp, they are active during the day and bask...corns really dont. they benefit from a heat source from the bottom. they like to burrow. they are mostly ground dwellers, not tree climbers.