They increase efficiency a lot (up to 40% for dual-axis trackers) but they also decrease ground a lot coverage, they increase cost of installation and cost of ownership, and they decrease availability.
See https://heliogen.com/
It's also a company which wants to sell heliostats, they're not going to tell you it sucks.
They increase efficiency a lot (up to 40% for dual-axis trackers) but they also decrease ground a lot coverage, they increase cost of installation and cost of ownership, and they decrease availability.