Everyone has tried to buy an item off someone before and usually the buyer would come across the word "offer" when he/she asks the seller how much?

I myself used to and sometimes still do this. But really, I want to know if everyone's incentive to say it is the same as mine.
Usually I say it because there might be a chance the buyer would pay more than my intended price.

Say a item in cs is 900k.

In my mind, I would sell like 600k, but what if the buyer is willing to pay 700k?

If I say 600k and he woulda bought it for 700k, I just lost a potential 100k more gold out of the trade.

But there are flaws to this. Like for example, if a seller tells a buyer to offer and the buyer offers lower than what expected, it usually results in a "no ty"

In that case, the buyer is like "then give me a price" and the seller would probably say nvm and end of any more interactions.

Anyways those are just a few personal examples but I wanna what you guys think about this.