Low voltage vs. regular lighting for closets: What are the technical and code considerations?
There are some requirements for mains voltage lamps in a closet NEC 410.goes over these requirements.
The advantage to These low voltage Low wattage lamps is the instructions allow them to be surface mounted without conduit. The transformer or supply can be used as a plug in or box mounted there is a switch in the model you listed. Code allows and even requires you to follow the manufacturers instructions so in that case where it may not be allowed with mains lighting it is possible when the instructions are followed.  So is one way easier?
Yes a simple system like you have can be run on the surface without conduit. Mains voltage requires boxes for splices these handy low voltage connections do not require boxes even if you run them inside the walls. I use low voltage rings for data and cable all the time a WBF-1 low voltage box eliminator provides a mounting surface for a low voltage Jack or plug in.
When it comes down to efficiency that is based on the quality of the LED 160lumens per watt is an efficient LED but smaller lower cost may only have 110 lumens per watt and that can be the same low voltage System or standard mains voltage lamps. The advantage with low voltage is plugging in &amp; surface mounting with just double stick tape in some brands (yours has screws).