See
this post for the dangers of the 5-9. The basic reason is that they rarely add significant high or low value to your hand. Sure A267 is usually playable, but you are usually going to have to make a nut low draw and straight draw on the flop to play this hand strongly. A flop that gives you a nut low and 2 pair is usually going to have to dodge straight draws to maintain a scoop, so this isn't terribly strong. With this hand, you need a nut low for security and then a really strong (2 pair or better) high hand in order to play it very strongly. A hand like AKT2 can also make nut lows and big one pair hands for high that might quarter or scoop. These hands are also playable on many all high flops and are also usually playabe with 2 high card flops. A hand like AKT2 just connects with so many more flops it should be clear that it is way better preflop than A267, which has only one advantage that it is easier to make a nut low with 2 pair.