Nothing really. So, when I started writing the install marketplace dev feature, I followed the steps that I used to follow by myself manually i.e. go to marketplace dev in the browser and install it. So I just automated that. Yes, its not much of use right now except if someone is in a real hurry and wants to install some other app directly from the browser. :P
Leaving the option there won't do any harm. But I can get rid of it if you want.