Not if the place doesn't do daylight savings time, and not all places in a timezone will do that (least in North America) so you need extra code if they do or do not. It becomes a pain after awhile when you do it in multiple projects. Technically one extra setting but it's still a pain to make sure it's handle properly in all cases, especially when the previous programmer decided to handle it for each case individually, but that's a different issue.

Also when you deal with the times, say in .Net you gotta make sure it's the proper kind of date otherwise it decides it's a local system date and will change it to system local when run. Sure it's all handled but there are many easy mistakes to make when working with time.

I probably didn't even get to the real reason, I sort of picked this up on my own.