It makes the app more portable for starters. This is mostly related to the differences in roles between bean developer and deployer.
The deployer will map your call to ejb/myBean to some instance bound into their namespace. in jboss this is done in Jboss.xml.
P.S. Yes there is a blurring of Developer/deployer really with developers often filling both roles, but I have developed in an environment where there wasnt that blurring believe me it makes a lot of sense when you do it in those conditions.