Someone else may have posted exact figures but I posted this about a year ago :
I did some maths not long ago where I worked out the value of 'Miles', based on what you spend versus what you can redeem them for. I don't have the figures to hand but I seem to recall that the miles earned, if you based the figures purely on a comparison of tickets, disregarding any other value added services, were worth a discount of about 0.5%. The only tangible value was 40kg allowance on all flights, as I used to bring a lot of wine and clothes back from SA. There were also frequent free upgrades, now a thing of the past too.
Last week I worked out that a BHX - CPT - BHX using my Flying Blue (KL/AF) Miles would cost me, in addition to the miles, just over £300. The cheapest consolidator ticket for the same flights would have cost me £370.
I realised what a waste of time these schemes are when after many years of frequent flying with LH, and reaching 'Senator' status, I was able to use the exalted Senator lounges in the German airports. On one occasion the hostess was showing me into the Senator Lounge at FRA and as we passed through the Business Class lounge, observed that the latter was less crowded and would probably be more comfortable! This was often the case, and the only 'advantage' I ever saw of the Senator Lounges was the possibility of rubbing shoulders with the rich and famous. The only person in that category whom I ever met and who was pleasant was, somewhat surprisingly in view of some of the roles she played, Grace Jones who was charm and Grace personified. What a lovely lady.
On a trip to Canada I desperately needed to get from YTO to YVR, I was waitlisted on several flights and went out the airport to standby. I'm not one of these people that likes to flash a gold card, but I did say to the lady at the ticket desk that I had a Lufthansa Senator card, or top level Star Alliance. She said : "That makes you a top customer of Lufthansa, but to us you are the same as anyone else." Since then I questioned the value of Alliances and Loyalty Schemes.
Like most marketing schemes, they simply give the customer an illusion of importance and value, whilst in reality he is being shafted.