For stable income its very necessary to choose top coins for long or atleast middle term. these coins give us more profit then saving.
Trader should use some trading strategy to make profit in trading otherwise it can also give loss or low profit.
If trader buy coins with every 20% dip and with every bullish season withdraw 10% ,one can make good profit than saving cash in bank.
I don't think any crypto investment could have a stable income since the price of the coins that we hold changing everytime, sometimes it's better to hold fiat and sometimes it's much better to hold cryptos.
Experts trader know where to save fiat before the market crash and know when to re enter when the market going to bullish.
But as an investors, holding for living is a motto that we are not aim for stable profits but big profits in the future.