- yes, people who just bought a lot of batteries are actually more likely to buy more batteries soon. same for people who just bought a fridge.
- these recommendations may cause some sort of "burn out", where people stop looking, responding, or decide to unsubscribe. But this wasn't much worse than other recommendations. including the awesome ones.
- the loss from burnout was greatly outpaced by the wins in actually targeting the right users
Yes, these are bottom-of-the-barrel recommendations. But they work. And people don't care that much even if they disagree. Maths said so.
I think this is a similar story to the complains on non-literal searches in search engines. People think they want one thing, but they want something else.