I'm sure if you wanted to invest a small amount you wouldn't be thinking of cashing it out after it grows like 2% within a month. for small amount to gain a considerable amount of profit, you would need the price of BTC to climb more than 400k or more so when you have small amount just forget it on your wallet. Withdraw them if you really needed such as small amount.
But why invest small when you can do bigger by DCAing as most people would suggest.
You don't no how some people are, they can still cash it out if they want to, no matter how little their investment is, however talking about small amount the two percentcan be $20 if the person has $1k and they think of removing it immediately, actually I'm not in support of quick removal of invested amount of Bitcoin but I'm statting that having small amount cannot change the mind of quick sellers because they reason that if they should be getting two percent they might be multiplying their capital in no time which is not an investment of a future goal.