But regardless of their estimation, we can always set the fee manually, no?
Only if wallet you use let you do that. Few wallet simply doesn't let you do that or only let you choose between few fee rate choice.
Oh, I din't know that. I'm just using Electrum and there you can add or remove even just 1 satoshi from your fee. ( I hadn't known it at first and was using the fee that Electrum was proposing me, but later, when the fees became unbearably high, figured it out.) So convenient!
You might be right. But even if you live in developed country, that money still could get you few lunch.
Yeah, it would be stupid to just throw the money away by anyone, even from a developed country.
This could be also some custodial service. For example withdrawal from an exchange/casino/other payment system.
Bad software exists everywhere...
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This is most likely the answer. No human would make such a mistake.