Chrome is also limited to 60 fps.
If there was broad support for going over that on the platforms Construct can run on then they would most likely try to match that.
Not that any of that really has much to do with performance or big games.
Those things are decided by the platform, and hardware. If you have less ram because you have overhead from the browser, or less speed because the browser does many other things besides running games then yes, there are some limitations.