For conservation mounting the goal is to be able to replace all of the framing components since overtime they get contaminated with atmospheric pollutants. This is generally a concern for museums trying to make things last forever. They will also story the items in temp/humidity controlled rooms, and even though they will use UV filter glazing they will limit the items exposure to light and primary keep them in the dark.
Drymounting makes the image a permanent part of the mounting board so if you do this you want to make sure the mounting board is archival if you want the print to last. Drymounting is very popular because it is the easiest way to ensure the print will remain flat.
High end collectors actually appreciate a little curl and wave in the paper since it indicate the image is not permanently mounted. The average consumer on the other hand views the curl or wave as a poor mounting job. It is usually cost effective if you understand your market and meet their desires.