Only if your night time temperatures drop below 60*F, at which time a correctly thermostatted heat mat may be attached to the side wall of the vivarium to keep night temperatures up at about 62-65*F.
For daytime heat it is useless, you are better off with a basking lamp.
Yep, agree with the above. They need their heat from above, as they bask in the sun naturally. So a bulb replicates that.
Heat mats are good for lizards such as leopard geckos as they lie on rocks and absorb the heat that the rock has taken in from the sun during the day...if that makes sense!