There are a number of reasons that the majority of collectors don’t gravitate towards coins that are damaged or notes that are heavily torn.
The first is that items like this just look plain awful!
We all often associate damage with accidents or injury, or even worse, with intentional vandalism.
Collectors really aren’t interested in owning much less admiring a coin or note that might’ve been damaged through rotten luck or outright malevolence, so they pass damaged items by until they see a coin or note that catches their eye.
Often, when collectors do end up owning a coin or note that has been damaged, they’ve compromised their own personal standards of quality in order to do so - they give up on having the real object of their desire, and settle on second best so they can satisfy their base urge to accumulate.
We all have a conscience that can be persistent in reminding us about that which is truly right, and many collectors find it hard to look at a coin or note that they bought during a moment of weakness without being reminded of their lack of discipline when it mattered most.
While we might understand that there are some collectors that simply want to satisfy their inner child that just loves to accumulate, quantity over quality certainly isn’t a strategy to follow if someone is trying to collect coins without losing money.
Many collectors are turned off completely by coins or notes that’ve been cleaned or otherwise altered by a previous owner - particularly when they understand that people that clean coins or flatten notes often do so out of greed - they try to make an item look better than it actually is, more to the point they try to make it look to be worth more than it actually is.
Such efforts are generally clumsy and easily detected by anyone with a modicum of experience - it is best to avoid the prospect of buying a sow’s ear instead of a silk purse and stick solely to buying coins and notes that are in original condition, or items that at least haven’t been tampered with.