However, if the price decreases, after you work hard to convince someone to invest and, at the same time, use your referral link, you will be attacked by accusations that everything is not going as your referral would like. Why do you need to have this headache?
I think convincing someone to invest in crypto without providing knowledge about crypto investment will be very risky, so always prioritize the word #DYOR when you convince other people to invest in crypto so that you won't be attacked because all investment decisions are up to each individual, even professional traders always reminded of the word #DYOR in signals distributed to private group members which indicates there is no guarantee of the signal results.
On the other hand, going back to the OP's story, many people are boastful. But boasting is a character trait of those people who like to assert themselves at the expense of others, those who try to prove their superiority literally in small things. Self-sufficient people know the value of their words and do not need proof that they are right. And when it comes to owning Bitcoin and generally speaking about their successful lives, they prefer to behave modestly while maintaining confidentiality.
They actually hide more losses than the profits they show off but the losses are never published, usually traders always show off profits from coin trading activities, but in fact they hide bigger losses. However, it's true as you said that traders never show off profits because they don't want others to follow that activity without any knowledge of market analysis.