That's the way it is in Win10 too, at least on my system. When I click on the Start button, the cursor in the Search bar starts flashing and I can type something.
Winkey +s does bring up the search Winkey by itself opens start. Once start open if you start typing it will search the computer so both actually work
It has always been this way. Even with Windows 8/8.1. All you had to do was press the start key on the keyboard and start typing. I never understood why people were so worked up about losing the start menu or even the start button when Windows 8 came out as I never changed my habits from Win7 and it all still worked. Only thing that was annoying about Win8 was it was more difficult to restart. They fixed that with 8.1.