descending priority in multi torrent

hey what do you think when it's about multi file torrent download if shareaza set by defaults descending priority so first files of the list/content will finishe first
is this can make a good change ? i mean a first files will be ready to use meanwhile the rest still downloading in stead of having all files on N %
or there's some technical issues (or some wastes) about making that? not efficient..?
is this can make a good change ? i mean a first files will be ready to use meanwhile the rest still downloading in stead of having all files on N %
or there's some technical issues (or some wastes) about making that? not efficient..?