There are many problems of hiring randomly and hastily:
1. Employees are usually the biggest expense and engineers are some of the priciest, so there goes the run rate (unless Alphabet foots the bill).
2. Hiring too quickly ruins the dynamic of existing teams and throws them into chaos.
3. Hiring too quickly tends to not apply good due-diligence because the few staff who are demonstrably good at hiring will be spread too thin to have an impact. This leads to hiring second- and third-stringers who will slow everyone down more than better hires, add to office political BS with their non-value-add/sabotaging drama, zap morale, and drive away A-players to their next adventure.
4. It may or may not be the case, but without a per-department plan to scale their organizations' resources (systems, budgets and staff) according to anticipated added demand to support massive numbers of new hires, that scaling too much in one area tends to overwhelm other departments. I hope they practice safe and sane scaling before it's too late.
PS: Dern, I could probably get a job there and I've been out-of-work for 9 years. Of course, it doesn't sound like a sustainable or happy place to work, more like a pressure-cooker that's hurrying to spend that money before daddy Alpha warbucks cuts off their allowance.