Maybe if you have 5000 mature coins, they are expected to stake after 24hours on average, but then you have to wait another 25 hours for them to mature again. So over time, the expected return should be half that or slightly less
At these prices, if 20k coins give 50 netko, that is 250k sat. So 1 BTC gives 0.0025 btc daily. That's almost 100% if you account for compounding too. You sure you know of a better PoS return from a serious coin? I don't care about random shitcoins that are created with 500% pos and are dead next month.
Of course even netko does not give such high rewards forever. Soon the stake difficulty will rise but it will be very good for years