- Make meetings accessible to everyone
- Communicate more effectively and transparently internal to the organization (and even externally, for the adventurous types)
The main "downsides" of working from home (which is not necessarily remote-first) - not seeing your colleagues in person, life <-> work separation, etc. will be a new industry that will end up resolving itself. I've seen office space costs. It would be cheaper to fly literally every employee out once a quarter and throw a giant party than to maintain an office space sized for the same amount of people by an order of magnitude in a large, popular city (NYC office space is approximately ~$100/sqft/month - a desk sized for two monitors, a keyboard and writing space is about 2 x 4 minimum, so 8sqft, or $800/month just for a single person in a nice space)
In other words, being forced to do anything - whether that was working from home or from an office - is an oppressive activity. Remote-first simply gives back that freedom of choice. Companies can maintain more minimalist offices for those who insist, and coworking spaces will grow for those who don't like the office and want separation, and finally those who have the space in their homes can work from home.
I'd be curious to hear a good argument against all organizations that can be remote-first being remote-first.