The experience of the person doing the advertisement or hype doesn't have to be exaggerated. If someone you know tells you about a huge profit they made trading crypto, it can all be true. But that doesn't mean you will be able to replicate it. It's possible that it was luck and a one-time thing.
The biggest mistake that beginners make is that they want to be traders but without having any knowledge about what they are doing except a few YouTube videos they watched and some very basic and limited understanding of the market. It's very dangerous to play with your money like that, and the chances are greater that you will fail than that you will succeed.
Basing your decisions solely on hype and feelings is a disaster waiting to happen. When it works out, it's pure luck and not skill on your part. Your luck could run out the next time you attempt it.
Doing deep research on the project, founders, team members, partners is time consuming, but the only way to mitigate risk for those who want to play around with alts.
Better yet, don't do it at all, and increase your bitcoin bags as much as you can.
Beginners are carried away by the success stories of friends and influencers who may have gotten lucky with a project, the excitement of the pump of their invested coin, will make them to turn overnight experts in dishing out cryptocurrency advice, newbies will then buy into these sincere hype and also invest heavily without knowing the credibility of the altcoin, the next thing is price will dump so hard that they'd lose their investment capital. This is why people that don't carry out proper research before buying a hyped project ends up calling cryptocurrency investment or trading a scam, because of their ugly experience, they'd blame everyone but themselves for their ignorance.
So it's important for anyone that wants to engage in crypto trading to get a proper knowledge of how it's done, learn the analysis necessary for a beginners, and for investment they need to carry out proper research on the project, founders and team members as you said, so they can atleast get a head start to understanding if it's a scam project. I agree that the safest cryptocurrency that you don't need to carry out any research before buying is Bitcoin, then top altcoins like Ethereum.