Well, I can't speak for others cause everyone has their reason why they need bitcoin, some need it for gambling while some see it use it for investments, but personally I do need bitcoin for earning online and also making transfers all over the global without stepping outside of my house, bitcoin just makes life much easier for me, honestly I don't have a bank account right now, but I'm still able to pay for good and service without a bank account , so yeah I do need bitcoin.
For new investors I think most times they make the mistake of buying at the top that's why they always lose their money at the first start, the existing holders are smart investors because they bought bitcoin at a cheaper price,probably it dipped to $5k usd as at March, those who bought the dip, bitcoin has triple their profit, it might hit the ATH this year, although no one knows, but I have a feeling it might, there's still much hype around bitcoin now.