What would you think if you sent a present to someone who had just had a baby and you received a baby announcement card, no personal message or anything, just announcing that baby has been born, name, weight etc? Do people think that's the same as a thank you card? Didn't even receive a text or anything to say thanks for the present.
Guess it's better than not receiving any thank you at all (which has happened a couple of times recently with baby presents I've given), but for me it's not the same as a thank you card or even just a text to say thanks if they're not doing thank you cards.