The problem of mining coins with low difficulty is that these are often new coins that are not even traded on the exchange, or there is a little-known on the exchange, small trading volumes and a low price.
What makes you doubt the profitability of mining.
Not all coins make a profit this way, but you can earn some money quite well.
The same thing could be said about the early days of bitcoin, people were making nothing mining a "worthless" digital currency and look where it ended up. Same thing happens to a lot of new altcoins you just have to be willing to take the risk.
Bitcoin is unique, and now go find the difference between some new 10 projects for mining coins. The actual difference is only in the names of the coins, most of them will die even before they have time to develop somehow.