Let's say I will disregard the response above that OP might promoting the exchange, the common reason why these newbies often using a non-popular crypto exchange is because of engaging on such projects promotions or bounties.
These coins/tokens can only be traded on those non-popular exchanges because it's quiet easy to be listed on those. Also on some cases, the project itselfs owns the platform.
Even those persons that I introduced in crypto are asking me some details about a certain exchanges on which I don't know where on the world they found it. Since they have no choice but to trade their reward coins there, then they have to face the risks.
On the main point, people should used their common sense in here. It's a dumb move to just deposit money on a non-popular exchange.