Basically a lot of hand positions is not the only thing you want, you want a lot of good hand positions. Drops are the winner because the ergo position is the palm vertical not horizontal position. I find from the hoods down I only have a few positions, but from the hoods up there are many. Altogether it amounts to the best positions.
Also, unless you are building custom, drops add extension to your position which is good for your breathing, but on a bike with a fixed top tube length, and a relatively fixed stem length, it can be a mater of the bars you choose dictating reach, so that is a factor.
The term "drop" is unfortunate because you can pretty much set bar height as you wish. But a lot of people are scared off the bars by pictures of time trial riders.