Exactly. The bass guitar was conceived as an electric alternative to the double-bass, which is tuned EADG. Orchestral music often requires the double-bass to play notes below bottom E which is why many basses are fitted with a C-extension. This requirement became more common in the late Romantic period and into the 20th Century and today a lot of professional double-bassists (especially in Europe) play five-string basses tuned BEADG or CEADG.Because that's how uprights were tuned.
No!!!! for Oktoberfest gigs you need to tune B-I-E-R!!!