It is a little limited if you are sending things through the post but not impossible :-). And if you are hand gifting your card - the possibilities for decorating your envelope are endless!!!
Why bother? I hear you ask, well - do you like that special gift just handed to you or do you like to rip off the wrapping paper and joke about keeping it for next year? It's just one of those things that make your card, and your effort just that little bit 'more' and especially if you are enclosing money or vouchers or a store-card.
Here are some envelopes I have decorated - fairly plain for sending through the post, a bit of masking and misting using Twiddleybitz coloursprays and ink, even running the envelope through my big shot!!
TFL - Mwah! XXX