OP, I whole heartedly agree with you but to put a slightly warmer glow on things:
I am shortly to be posted overseas with wife and child (will be 2 months old!). As far as I can see the LOA will not cover the cost of living there. However, I volunteered and am still looking forward to going.
To those whiners disagreeing about loss of earnigns for partners, yes they may have to give up a job when you are reposted in the UK but the chances are they are fluent in English (or some colloquial version) and will not have a probelm getting a job (yes apparently the number of unemplyed is increasing but that is because people are not willing to take any job that is available).
With a foreign posting (non English speaking country) this is far more difficult, especially as partners no longer receive language training at all.
The cost of car ownership has also been raised. Even if you take your existing car(s) with you you have to pay for license plates and registration for the new country of posting. A new car is an option but will cost as much as it would in the UK (unless you can buy outright without finance). Not a saving comared to the UK but not more expensive either.
Overall, although I will take a financial hit there are a number of positives.
Fuel allowance has increased to give you more litres tax free. As you do not have to worry about flights/car hire or ferry costs, europe becomes vastly closer and easier to explore.
We have decided the wife will be a stay at home mum so she would have lost her income anyway. A plus point is we will be able to claim child benefit from our exchange countries givernment (something the government here is still fighting to stop). Our child will also (hopefully) be bi-lingual by the time we leave.
Overall, a financial hit (which should never be the case despite what some of the old stalwarts say) but we have decided to accept this due to the opportunities it gives for us as a family (provided we make the most of it).
I wouldn't say carte blanche don't take an overseas posting, weigh up the pros (opportunities) and cons (costs) and see if it is for you.