I think the point of gift vouchers is for the giver to appear more thoughtful and caring than he or she would seem if they just handed over cash. OK for children, who prefer it, but adults feel the voucher indicated that giverhas thought about them. That's the theory.
Yes, Tunesmith, I agree. Years ago the small HMV two floor Exeter shop had two or three racks for folk, blues, country, classical, MOR etc; on my last visit all the racks were Rock & Pop except one which was 'other' and, yes, it was everything else, the lot.