We have been using drip tape for about 5 years to water the vegetables in a dry time.
We do not lay the flat drip tape below the surface of the soil. It would be difficult to detect problems in the tape if it was below the surface.
The water pushes the soil particles away from the pipe so the soil does not clog our tape. Roots could be a problem if it is down for some time, but we have not had a problem with roots. It could depend on the quality of the tape.
Alkaline soils cause the tape to block with lime scale. The tape has then to be unblocked with acid & this is easier to do & manage if the tape is on the surface.
We are in the UK, where the climate is temperate. So the tape does not get very hot, & expand. In hot countries, the tape will expand in the heat & wiggle about a bit, which may make harvesting difficult if you are trying to avoid the tape.
The tape will be damaged if a reaping machine catches it. But gardeners using a hand-held fork (to dig potatoes) will also damage the tape if they are not careful. Because of this I lay the drip line on the surface down the row, and remember where it is, so that I can avoid it when harvesting.
The evaporation loss, because it is on the surface, is insignificant.
Using drip tape with care protects it so that it can be used year after year.