The first two offer
terrible award values and Malaysia, which is slightly better, has a convoluted booking process.
Not exact matches
For example, see the New British Airways Avios Devaluation which really made first class and business class
awards a
terrible value, especially for peak travel dates on British Airways and on partners, since all partner
awards are at the peak travel rate.
In other words, you'll never get a great or
terrible deal on an
award flight because you'll always pay the market
value.
They use a distance based chart that offers fantastic
value for short haul
awards yet the
value equation for long haul
awards is
terrible.
But, as is usually the case in ANY of these programs, buying points / miles outright is almost always a
terrible value and should only be done when you need a small number to reach a certain
award ticket level or something like that.