I can't speak for the tech guys, but I think one of the reasons they avoid uploading images is that it can really slow down loading on a site. Not sure if this is still a problem today with most people on broadband, but it would be for anyone with a slow connection.
You need to have space to STORE the images plus pay for the bandwidth of downloading them. And once they're available on your website you have the problem of people linking directly to the photos from other message boards or web pages at which point the hosting site pays for the bandwidth and storage and other people are freeloaders. Photobucket has a business model that somehow makes this work but TriS does not.