It depends but IMO it should be a "yes" to say low market cap are better for investment (Case by case)

Reason why: High marketcap coins are usually reputable, hype-able, develop-able which will make a high marketcap higher

But low marketcap coins are usually coins that belongs to 70-80% Junk, 10% gems and 10% others.

For people who are searching for risky yet real quick gain, yeah. Low marketcap is better for investment