[Nepomuk] properties range and RDF literals

[Evstifeev Roman]

Looking at those two properties:
1) nfo:fileName
      rdfs:range <http://www.w3.org/2001/XMLSchema#string>
2) nao:description
      rdfs:range <http://www.w3.org/2000/01/rdf-schema#Literal>

am i right, that:
nfo:fileName here have range of typed RDF literal of type xsd:string
nao:description have range of some RDF literal (typed or plain)

and second:
why range of those properties are different? It seems to me, that 
nao:description only will ever contain a string too, and range of any RDF 
lieral is useless here. (for ex. using xsd:integer as a description is weird)