Its easy to call it a bubble/scheme because most things usually are. The fundamental difference with bitcoin is that it is unlike anything the world has ever seen. Given the limited quantity and proven utility of it, many people believe it is still undervalued and maintain price targets in the tens of thousands upwards to hundreds of thousands. These targets are derived from simple calculations.

The only question is whether or not bitcoin will maintain its utility going forward. As long as it does then the value will continue to rise.

Do yourself a favor and hedge your one-sided, possibly wrong opinion and own some BTC sooner than later.