One of the issues that arises when you use a bike posture that has you leaning way down on the drops with your saddle higher up is that it tends to take your weight off your sit bones and put more pressure on your front girl parts. The more extreme the leaning down position, the more difficult it becomes to find a comfortable saddle solution. If you read this forum for a period of several years, you can see that this, along with the typical woman's reach problem, are the two most common biking problems we women seem to have trouble with.
This frontal pressure issue is sometimes not such an issue if you are racing or doing short fast club rides, but can certainly become more of a problem in longer distance rides like touring. That's really why touring bikes tend to have you sitting a little more upright.
It's rather tricky to balance speed and comfort. Can be done, but it can get complicated to find the right solution for each person.