1) Dressing up in a button-down or a suit or a dress and high heels. Sitting down at tables around $300 bottles of Grey Goose. Pop music, hip-hop, electrohouse. Crowd is mostly straight, most attendees are there with the intention of meeting a sexual partner. You stay for 1-3 hours, mostly talk and get wasted and dance a bit.
2) Dressing in casual clothing or streetwear-oriented fashion with comfortable shoes for dancing. Few or no tables - the dancefloor is the primary attraction. More drugs than drinks. Crowd skews alternative with strong LGBT presence. People are there for the music, which is generally repetitive electronic music, house or techno or DnB etc. You stay for 3-8 hours, mostly dancing and talking to friends, drinking but probably not getting drunk.
This article is mostly discussing the second category, but I'm not sure how familiar American readers will be with this style of club - my understanding is that it's primarily a European phenomenon, with outshoots in some key non-European cities (NYC, Detroit, Sao Paulo, Tokyo to name a few). These clubs are closer in concept to American raves, except at dedicated club venues. These spaces have historically been incredibly important for minority communities (queer, black, latino) also for musicians. They foster the cutting-edge of underground electronic music, which eventually filters down to shape the next generation of radio pop. Berghain, the club mentioned at the start of the article, is the prototypical example of such a venue.
I don't care for the first category of clubs and I don't attend them, but it would be a huge loss to culture if the second style of club disappears. It was already struggling pre-Covid, with many clubs in London doubling as event spaces or art spaces during the day in order to raise more money.