Sunroofs provide a nice airflow through the vehicle. Aircon drys the air and some people don't like that. My wife always turns the air con off. I work in computer rooms so i guess I'm used to it.
What I cannot stand is cabriolet car. Just seems odd driving a car without a roof.
Plus years ago in East London - I fitted a clutch to a yellow Saab 9-3 - took it for a road test - black lad on a mountain bike rode past as I was in a traffic jam and launched a Banana thickshake into the interior and cycled off. I was covered and so was the inside of the glass and the beige leather interior.
My 03 plate Disco 2 ES had twin sunroofs and yes they leaked.
I dropped the headlining out, sunroof frames out, resealed the frames and fitted new rubber seals, job done
Its a common misconception that if the drains block then you will get water in, not true, if you are getting water in then either the sealant between the frame and roof has failed or the glass seals need changing.
Thats not to say that the drains don't need to be unblocked as if you do get water in either past the seals or under the frames then the drains help get it away
If you have ever had the frames out then its pretty apparent the drains are a last resort
If its an off roader, leave them sealed up and disconnect the switches