I'm another player that studies the kingdom at the start, but I have a message that I cut and paste into chat to let my opponent(s) know that I am doing so. Originally I didn't click to start the game until after I'd finished looking at the kingdom, but one or two players pointed out to me that it would better to do so before studying (they were right), so that's what I now do.
The only justification I can see for showing players their deck initially is that it ensures that someone with a $5 start knows whether they are playing a Shelters or an Estates game (if I recall correctly the presence of Heirlooms, but not of Shelters, is obvious if one studies the kingdom). That same information could, however, be presented in the log by stating the content of the deck. If that were done, then I'd agree that there is absolutely no need for the delay before seeing one's initial hand.