Picasa vs. Flickr

Why does Google's Picasa web Albums still lag behind Flickr in versatility? In Flickr I can adjust the date for an image in a field. This is especially important when I scan an historical image. I want the date to be the date the image was taken, not the date that it was scanned that Google takes from the meta data. Flickr also lets me sort the images in any folder by the date. This adds utility to any folder. I can watch myself age as I progress through images of my youth to my current age. Scanned articles are now in chronological order. Flickr also has flexibility in the date fields for historical images so I can just pick a year, or just a month and a year. There is also a "circa" box I can check to let someone in the future know that there is uncertainty built into the date.