The lining pocket is usefull for small things as money, small notes of paper or your cellphone instead of allways have to dive in to your sporran every time. Of course if you put some bulky objects in the pocket it may show trough the aporns. Things will also show more if you have two straps on the front apron.
I think the "Piper pocket" looks smart too. But non of these pockets are usefull for heavy or bulky objects.
Skål!