It's not the most frequent method for launching. According to MS, their metrics indicate pinned task bar items are, or are trending to be, the most frequent method.
When I don't remember the name of the thing I want to launch (which is quite frequent), I rely mostly on positional navigation through a customized start menu. That is, I don't remember programs by name, I remember them by where I left them. Windows Vista / 7's start menu was a major regression for my use case (the scrollable treeview with expandable items destroyed absolute screen positioning); I had to replace it with Classic Shell to get usability back.
When I don't remember the name of the thing I want to launch (which is quite frequent), I rely mostly on positional navigation through a customized start menu. That is, I don't remember programs by name, I remember them by where I left them. Windows Vista / 7's start menu was a major regression for my use case (the scrollable treeview with expandable items destroyed absolute screen positioning); I had to replace it with Classic Shell to get usability back.