A new investor may find that he held a coin, there was no 10% pump and the coin is now worth 20% less than a year before. He can sell at a loss or hold a bag forever like people who bought all those new PoS coins last year.
In that case, we have to choose some coins that have good potential such as bitcoin, altcoin, ethereum, waves, monero, nem, and so on. 10% isn't so big to achieved and may take 1 week or 1 month to reach it, depending on current market trends. For example, bitcoin fell to $17,6k 3 days ago but managed to increase up to $19,4k yesterday, so it has achieved a 10% increase. Nevertheless, limiting profits to just 10% is indeed an advantage, but some coins like bitcoin have the potential to grow more than that, so we can wait a little longer to take 20% or 30% profit.