You can't make profits by doing this. Because BTC price goes up and down every day, if you do it this converting again and again, then your profits will be zero but the loss will have numbers. You have to be brave in trade, otherwise, you can't do well in trade.
What is converting here? Every trader who trades bitcoin against fiat, must need to buy or sell bitcoins and USD more frequently which has no differences from what you mean by "converting". If you do this randomly then definitely you will lose all your capital and if you do this carefully like selling higher than buying then you are doing the actual trading (assuming at your selling price that you are covering all your fees+some profits).
Loss and profit both are common here, sometimes you may lose, but that doesn't mean you end here, rather be strong and customize the trading strategy.
Yes, even decades long experienced traders too must be booking losses time to time. But, they must be booking more profits than losses which is the reason they are able to continue their trading. To do so, you must need a strategy.