If you're in a dim environment, a glossy screen has slightly better contrast and colours. If you have a light source or bright objects nearby where their light falls on the screen, a glossy screen has significantly better contrast and colours, as long as the screen and you are positioned such that you don't see the reflections. If you can't avoid reflections, e.g. because you're outside in bright sunlight, a glossy screen is pretty much useless. But if you mostly have a notebook so you can take it to different indoor workplaces with suitable lighting, and/or so you can move from your desk to a couch or bed (e.g. to watch a movie), the reduced glare can be very nice to have.
So the thing is, if you never had one yourself and only observed others using them while away from their preferred work spaces, chances are you've literally seen glossy screens in a bad light :)
Of course, if your use cases are all text based, the potentially better picture quality of a glossy screen is indeed rather pointless. Either option is a compromise; what's better depends entirely on where and for what you use the device.
Glossy screens generally have more vibrant colours; matte is inherently somewhat muted; and in some scenarios have better contrast and brightness.
(Also: PRETTY! and APPLE! are important psychological factors as well :P. Joking aside, many people will look at vibrant screen and how pretty it looks and make their decision without considering the specs, details and use cases )
For myself, in most situations glossy screens mostly mean I can see everybody behind me better than I can see my work; but they do have their place, especially for professional design/video/photo work IN (and this cannot be overstated) well controlled environment (basically, make everything BUT the screen non-reflective / control the light:).
I tried to put one on my 13" MBP a while back, because I hate how glossy and reflective the screen is. Was horrible to apply, and I ended up with lots of small scratches in the laptop display simply by gently pushing out the air bubbles with a card... I won't be applying a screen protector again in a hurry!
> The desaturation and softness are (AFAIK) inherent to matte screen surfaces and the reason manufacturers nowadays tend to avoid them
If it has to be a choice, then I choose matte regardless.
So the thing is, if you never had one yourself and only observed others using them while away from their preferred work spaces, chances are you've literally seen glossy screens in a bad light :)
Of course, if your use cases are all text based, the potentially better picture quality of a glossy screen is indeed rather pointless. Either option is a compromise; what's better depends entirely on where and for what you use the device.