It is an interesting idea, but how much is is the annual subscription? Presumably less than $60?...but then the developers are losing money (I don't think the savings from shipping and packaging are going to cover it.)
A monthly subcription is a tricky subject as well. If I don't subscribe for 6 months, can I subscribe for one month and get all the updates from the prior six monhts, and then drop my subscription after one month?....wait another 6 months and do the same?