Spending money I'd spend at a brick and mortar store, that I'd have to drive to using oil life/tire life/gasoline/brake pad life/brake rotor life while also losing time.
Instead, I can think "oh hey I need to get a shoe horn, the heels on the uppers of the slip-ons I wear to church are getting funky" or "ah crap, I forgot to stop and get a new belt on the way home and this one is getting pretty loose on the last notch and I don't think this synthetic material is going to be happy if I punch a new hole" or "instead of driving to 6 stores hoping to find filters for my air purifier, I can buy 2 on Amazon right here on the toilet and be good for the next 2 years" and "my xlear nasal spray is about empty here at work and this heat is really drying my nose out, I'll just order another now instead of waiting until I go to the grocery Saturday" and "I need another USB C cable, this one is starting to get pretty stressed, I'll order one on Amazon instead of driving miles out of my way to go to Walmart or Best Buy hoping they have one".
Those are this week's purchases. All things I needed, all things I would have had to buy somewhere, all things I got a 1$ credit for which I will use towards eBooks I would have purchased either way.
Or last week when I ordered a tofu press, I have no idea where to buy a tofu press in the real world but wasting gobs of paper towels and using books just wasn't doing it for me.
It's not like I opened Amazon in a moment of boredom and said "let's see what I should waste money on today".