profitability for mining at this point for crypto shouldn't be what we should look at but sustainability. Its going to take a lot of time to achieve the success rate you desire to get with Mineblock or any mining services at this time.
Apart from traders who trade daily, those who have been in the game for long know that holding and token means you are holding for long. Short term holds don't usually end well.
if there is something i have learned from market behaviour it is that long term holding is one sure way of making profit but holding for long is usually not a consideration for investors because too long can be bad at times