Offer your thoughts or opinion on the input financial query or topic using your financial background.

Debit cards as bad as credit cards?
This sounds more like a behavioral than a debit card issue to me TBH. Did you put the money you're putting away into a separate savings account that you (mentally) labelled 'for investment'? That's pretty much what I do (and I have a couple of savings accounts for exactly that reason) and even though I know I've got $x in the savings accounts, the debit card I carry only lets me spend money from my main bank account. By the time I've transferred the money, the urge to spend has usually gone away, even though it often only takes seconds to make the transfer.