proof of stake is not safe. Poof of work is power hungry. Choose one.
Proof of stake is considered unsafe because one person holding big amount of coins could fork the blockchain. Low difficulty if people are offline = forked blockchain. But proof of work also has 51% attack.
While your statements are the common sentiment when it comes to comparing Proof-Of-Stake and Proof-Of-Work, it is not necessarily always correct. The argument that POS is weaker in terms of security is only because that it is extremely young technology. As developers and companies build out this tech, it will soon reach levels of security unparalleled even by POW. This is the natural course of evolution and innovation. There will be always be some new invention that will make existing tech obsolete.