Waivers in the NHL are a complicated business. For most players on regular waivers, the intention of the team who waived them is to send them to the AHL, not to never see them again. Sometimes the team wants a player claimed, but not often.
Occasionally a team has both of their extra goalies claimed in one day. Goalies are almost a special category when discussing waivers, however, since it’s not exactly uncommon for a team to claim a goalie for a short term injury replacement and then not need them later.
Carolina claimed Curtis McElhinney largely because Scott Darling has an injury that will keep him out for a short period of time, according to current reports.