There was 1000s of online investment and get rich quick scams before Bitcoin even existed and there's still masses of them that scam people out of traditional currencies too, but as soon as Bitcoin happens to be used the media make a big thing of linking it to Bitcoin so people start seeing it as a flaw with the currency making Bitcoin have a bad reputation for criminal activity, but it's just online cash even though USA tax it as assets despite the
SEC chairman stating the following recently, "Replace the dollar, the yen, the euro with Bitcoin. That type of currency is not a security.". Criminals will use what is available, it's not a flaw with the currency and it's not a flaw with the Dollar when criminals use that either. The vast majority of users and investors of Bitcoin are legitimate.
PS: Bitcoin is pretty low at the moment compared to December 2017 at around $7300 at the time of writing, but it's still much higher than the start of 2017 and the December 2017 peak was in my opinion created mainly by media hype that it couldn't possibly sustain so early in Bitcoin's development. Another reason for the drop is regulation fears, although so far it has been fairly promising, investors are still very fearful at the moment. Also there's a defunct exchange called Mt. Gox where the trustee keep selling masses of Bitcoin in batches causing the price to drop, even when they're not selling the fear is stopping some investors from buying. It is likely to all pass however and there's now a lot more corporate investment that is increasing, in my opinion the price will substantially increase again in the long term, although it's likely to be a rocky road.