Many people find using the keyboard much quicker and more convenient than the mouse. Find In Files is easy to use with the keyboard right up until you hit the folder browse button.
Type in the first part of a folder name, then tab to Browse and hit space. Browse For Folder opens - but you can't use it without resorting to the mouse! At least, I just discovered that the folder list is in the tab order - but it's almost impossible to see that when the current folder is not visible in the scroll window: it looks as if the tab order is restricted to the buttons.
A couple of enhancements would make this control so much friendlier:
Start with the focus on the list of folders, not the buttons.
Scroll the list so that the currently selected folder is visible.
