Why in adds all watches are showing 10 pass 10?

Do they ?

I must have had nothing to do... I just looked at 30 watch advertisements from 30 different companies. None of them had 10:10. Some were 6, or 5:15 most were all random times.

So, it is perhaps, merely the ad company you noticed, uses the same watch for sales ads

It's purely a question of what looks nice. Many watch ads use 10:10 because it has a relatively pleasing aesthetic look, as the hands appear "balanced." Also the upwards "V" configuration is nice - like a happy face as opposed to a downwards "V' that you have with 8:20. Finally, since many watch manufacturers place their logo on the watch face under the 12:00 position, the 10:10 'V' nicely frames and emphasizes the logo.