We use WeWork as an office space and have for almost 2 years. It isn't cheap, lets be honest. it costs ~$200/sqft. Compare that to an average $35/sqft for typical office space. But ,you get a slew of amenities.
The fact you can do month to month when any other lease will be at least 1y locked and and 3-5y mandatory locked in as a general rule. That isn't congruent to companies getting off the ground.
So, WeWork does offer great flexibility - but at a slightly marked up cost.
We'd never sign a 3y lease, it would be way too expensive and we'd never be able to gauge what we need in 3y. The trade off with WeWork, at least for us, is worth it.
Next year we will be looking for some private office space.