This is a fair point.
When private investors buy shares in companies, they often want to find a bargain and avoid companies which have been doing well and are at, or near, all time highs because "they're too expensive", but quality tends to lead to more quality.
Plainly the argument falls down a bit with BitCoin because, apart from the old adage about something being worth what people are prepared to pay for it, it's hard to quantify what it's worth today, never mind what it'll be worth in a  week / month / year /decade, so, as long as people understand the risk, then go for it.
For the record, I still hope it crashes and Kev loses a paper fortune though. In a perverse way, that would give me pleasure.