Of course it's good to read Heavenletters however you read them. I know many people read Heavenletters on the website. If we could get Heavenletters onto the back of cereal boxes, that would be great too! (Hmm, how do we get God quotes onto the back of cereal boxes?)
Yet I strongly encourage everyone to actually subscribe.
I have the idea that something special happens as every Heavenletter is sent out. The more subscribers, the more often Heavenletters cross the Universe. The more Heavenletters sent out, the more powerful it is. I don't know how it works, but It may be that every subscriber is worth a hundred subscribers. I do feel that there is something like that going on.
I also feel that for the individual who receives the Heavenletter, there is something extra as well. A Heavenletter goes into your inbox. God's messages are addressed to you. It seems to me that that has to be more powerful.
I also like to think that Heavenletters sent to us somehow neutralize all the spam and junk mail that come uninvited to our inboxes.
I just think it's a good idea for everyone to invite God into their home.