4 s to full power? It's not long. To save money, of course (some start up to 15-20 s). ;-) Anyway - if it starts up, it's not damaged. If you need a faster reaction, "go back" to the classic light bulb or, on the contrary, get the latest one - the LED. You can use this one somewhere where there is no need for a fast start-up and where it lights up longer ("flashing" does not help).