This can be very effective, which is why optimising complex pages for first contentful draw (perhaps at the expense of overall load speed) can make a huge difference to how your pages/app are perceived.
Back in the dial-up (and early ADSL) days many were convinced that IE was faster because of progress bar trickery: it would actively lie and could inch up to ~85% before the first byte of data had arrived from the server (I forget if it waited for the HTTP request to be sent or if it started edging up immediately upon TCP connection). It still did it right up to the end, though with local connectivity getting faster these days the amount you'll notice it is greatly reduced.