It is essential to understand that no one cares about what you have put in Bitcoin; so, do not invest with the intention of showing off without conducting any study into what you are investing in. Even if you are investing in Bitcoin, be sure you understand the fundamentals behind what you are doing and do not invest with the intention of making quick money.
I don't think people do it to show off. Most people that invest without having an understanding of Bitcoin just want to make a profit, which is good because that is the whole idea of investing, but it's not right to just dive into something without understanding at least the basics of that thing.
Most of these guys don't just want to miss out on an opportunity. It's why people easily fall for shitcoin scams and Ponzi schemes. When a person is too eager and desperate to make quick money, they'll most likely fall into the wrong hands.
Always avoid borrowing money for Investments.
Actually, it depends.
People borrow to start up businesses. A business can be seen as a form of investment.
There are crypto traders who have people invest with them. They collect money from people, trade the money, and give the investors their share of the profit. A Very risky business, I don't advise it.
Personally (and this is not financial advice in any way), I think it is only okay to borrow for an investment when you have in-depth knowledge of that particular investment, with some experience. And even as you borrow, make sure it's something that you'll be able to land on your feet if things go wrong.