Looks like they use Transcranial Alternating Current Stimulation (tACS).
The military has been doing tDCS (direct current) experiments for a while for increased learning & performance.
I had a friend who used to swear by tDCS and did it very frequently. He attributed all kinds of mood & cognition improvements to it, including substantially reduced need for sleep, improved eyesight (he was born partially blind), etc. He also complained about migraines a lot and liked to experiment with all kinds of supplements, so YMMV.
Tried tDCS myself a handful of times, not for improved learning but for improved focus. If applied correctly it definitely has an effect that I'd consider better / stronger than a cup of coffee. I wouldn't feel comfortable doing it regularly though.
Circle seems to be far from a Goldman subsidiary. According to Crunchbase Goldman invested once in their Series C. If anything the Bloomberg headline seems to overplay the Goldman connection.
I'm in the middle of converting a small production Rails API + Ember app to Rails Views + Vue.js using webpacker and a lot of the techniques discussed. It's certainly been a learning curve, but I'm definitely happier with the new setup for all of the reasons you mentioned.
It's not a one-size-fits-all solution, but for a single dev / small team working on a web-only application it can make a lot of sense.
I agree. Even if it's a bit of a roundup post, there's limited material on this stuff in general. Even small tidbits on process or philosophy are helpful.