There have been several comments along the lines that using 3V cards is time wasting and/or a bit of a faff.

Undoubtably true, but there is one factor worth considering which is almost indefinable - the ability to pay HMRC or Council Tax indirectly by American Express without paying a surcharge and earning MRs/BA Miles AND Tesco Clubcard points at a useful rate at the same time, leading to smug satisfaction.

If for that reason alone, they're worth it to me. I've only bought them recently using Helping Hand and Clubcard conditional spend vouchers, and these also make the Visa gift cards with a fee worth purchasing.