Good point on the range, Leenia; but do note that the hymnals are generally scored for the congregation, who are not expected to be trained singers. Choral (churchy) music for the choir is quite frequently scored for trained singers who are expected to have much fuller ranges. (Try Handel's "Messiah" sometime when you have a cold - guaranteed to hurt ya, regardless of which part you sing.)

Music of the operetta kind are generally a little less demanding than operatic, but the solos are generally expected to be assigned to those with a bit more range than the backup singers. An operetta piece might well be set outside the range of most of us, and a key change would be in order for solo use.

John