Hello,
It makes everything brighter of course. As far as colors are concerned, you can calibrate on any brightness but changing it back and forth won't give you accurate colors at 2 or more brightness levels at once.
On TV's however, there is (typically) a backlight option (your laptop doesn't have this option), which is a much better option.
It can be confusing, because your laptop has a backlight, but you're adjusting the brightness. Brightness on your monitor is directly going to affect your contrast as well. Typically first you adjust brightness, then contrast, then brightness again.
The only backlight on laptops that you can adjust is the LED's behind the keyboard. Unless of course I'm mistaken, and your particular model have both brightness and backlight, or manufacturer simply don't understand the difference.
All the best!