For what it's worth, the email address for receipt thing is not always a marketing scam. Home Depot asks if you want a receipt emailed to you, and they have never sent marketing emails. Furthermore, they link the email address with the card you used to pay, so the next time you buy something it auto-fills the email address field. If it's a one-off purchase it's not worth it, but if you buy stuff there all the time (often expensive stuff that might need to be returned), having emailed receipts is great.

Home depot also lets you choose email receipt or paper. This time it was a case of just "what's your email so we can send you the receipt"