Most of the crypto in the OP requires trusted setup phases and is too slow to use for any kind of general-purpose computation. It's the reason why most cryptographic protocols consist of simpler schemes and don't try to do everything. This article is click bait though. Feel like OP just stumbled upon what people have been doing for the past 5 years and wrote this half-baked article on it.
This was true 3 years ago but not generally the case anymore. There's been significant advancements to move away from trusted setups and the speedups with current methods are quickly approaching viability.