If the Wx requires instrument approaches then we use the ILS on rwy 20, or non precision on either 02 or 20. There are no instrument appproaches to 26. Can't be used at night either.
We use runways because of the class of approach we do and for safety reasons. better to land on a runway than a field when you have wheels! If we had great performance and unlimited power margins, then yes, helipads would be great. We do have one published approach/departure which takes us direct from Charlie taxiway to the east, or vice-versa. A lot of the guys don't like using it though and we can only do it with the wind in the right direction and no passengers.
It's all to do with public transport ops.