If you ignore CAC, Zapier isn’t a company that is going to lose any money per new premium customer. And we know this since they offer a free version with the premium version only having a few extra features. If they offered a year it would be one thing but 3 months means that for 75% of the rest of the Coronavirus period the small business will be paying them.
So what’s the charity here ? None.
Think of GameStop calling themselves an essential business in states on mandatory lockdown... not great PR.
Or like the box.com model with a "install this behind your companies back, and once enough of you reach a critical mass where its painful to undo, they wont be able to ignore it anymore, and the ramifications will be their problem not yours."