it's definitely good. but why u would need it? i mean, obviously u r not gonna download a 900 Mb game over 3g. that will cost u like anything. and not over 2g. it's gonna cost u days and a very heated phone.
there are times you don't have access to Wi-Fi and store limit is not 900 MB but only 100 MB and 3G can be enough for it. also Wi-Fi or not, you don't have to download a game once on each device if your friends have WP. it depends on the occasion if someone needs it or not . but more option are always better.