I don't think small investments can make sense. It's just like a lottery and rarely it works. So if you want to look for a bigger chance for success , spend more funds in it.
Small investment will grow very slow and other than as learning step, such investment won't give us anything. For me, it is just a wasting of time.
If one does not have big money to start investing it is better to start with whatever they have first instead of waiting for them to accumulate big amount. Because if they start with a small amount then their risks also and they will get time to learn about smaller risks.
Don't ever underestimate small amounts because if you bought last year NEO or ETH at a very cheap price like for a single digit number and spend just only 50$. Today's worth will be in thousands.