It's better to hold fewer coins as long as it has the potential to grow in the future whereas holding lots of coins but with low possibilities and potential to gain investors in the future. It's like you were holding lots of stone instead of holding those rare gems which is more valuable than those stones that you were holding.
Fewer and better, better have coins that have potential and at the same time we're able to managed. It's hard to have many coins and then will just hold it but not been able to get updates and happenings on such coin. We must have time to read teams update so we can decide on when to sell or to buy more of that coin.