The MELF SMD resistors are used for a number of reasons:
MELF resistors provide a high level of reliability.
A MELF resistor has a more predictable pulse handling capacity than other SMD resistors
MELF resistors can be manufactured with tolerances as tight as 0.1%
They can be manufactured with very low levels of temperature coefficient, sometimes as low as 5 ppm/°C
Overall the cylindrical construction of MELF resistors provides an optimal power rating and pulse load capability related to the mounting space.Although the standard flat chip resistors are cheaper and much easier to handle during manufacture, the performance of MELF resistor can be an overriding factor making them a cost effective solution