Trust isn't binary & is necessary for humans to co-operate. 

You trust people to adhere to driving protocols every time that you get in your car.

How you mitigate the risks that come with trusting individuals is a personal decision.

I'd rather place a small amount of trust in the individuals I do business with than a large amount of trust in a govt or institution. 

WoT is about increasing the cost of breaching trust rather than eliminating the breaches completely. Trust should be in the provider of the value rather than in the consumer or the money. 

 I'm not buying a thing that is called Web of Trust. It doesn't exist and will not gonna save anyone on internet 

 Nobody's selling much of anything yet but I imagine a WoT will be useful when people start selling.

The risk involved with following an npub is pretty low & so a WoT is really only useful for discovery/algorithmic based feeds.