I don't know if it will save us or ruin us, neither I think they can do everything. But even at current point they can do a lot, and there are countless types of work they already are capable of automating significantly (for example, something that took 4 hours now can take 30 minutes, or something that took 10 people now can be done with just 2). And that is definitely something that shouldn't be ignored in environmental concerns. Network effect might actually be a huge win in terms of electricity and emissions. In terms of economy though, people should at least get UBI or something similar for this to not turn into a total economic collapse.