I've largely given up on the Executive Club and agree, to some extent, with the correspondent above that it's a "con". I'm inclined to think that one of the reasons why BA refuses to consolidate fuel surcharges into basic ticket prices is the potential loss of revenue from redemption tickets. I, too, have BA Miles in my account doing nothing.
For illustrative purposes, I chose random dates for redemption flights with BA on the Gatwick-Malaga route as this is one I'd like to be able fly redeeming BA Miles.
BA wanted £63.10 (i.e., its taxes, fees and surcharges) plus 15000 Miles for a return booking. Now, to be fair to BA, £10 of this is APD so let's say £53.10. EasyJet for the same dates was £51.77 whilst Ryanair from Stansted was just £19.98.
I realise that the picture will look different for other routes/dates; that using Miles for upgrades can "save" thousands of pounds (I know, I've done it); that I'm not comparing like-for-like (e.g., on BA I'll get a sandwich and a drink which Ryanair and easyJet charge for); that I use OLCI, do not take hold luggage etc., which would change the easyJet/Ryanair totals; but I think the general picture is clear: what would be the point of my using BA Miles?
I accept, too, that other airlines do the same (I have bmi Destinations Miles sitting unused for the same reason). However, it has not always been this way. I remember in the past (before APD, admittedly) when I received genuinely free tickets from the KLM Flying Dutchman programme.
(P.S. To earn 15000 Miles for the flight above using my BA American Express card would entail £15000 expenditure. The same level of spend on easyJet's MasterCard would entitle one to £150 off easyJet flights.)