I’ve used Google Fonts in prototypes and in 10M+ MAU products. It’s incredibly easy to get started with and provides an amazing font discovery. That’s also why it’s currently still used on over 42M websites!
This convenience has its price: Performance. Many have already pointed out the cost of multiple requests. If you want the remaining speed boost, then you’re best off downloading your used Google Fonts and self-host them.
This is nothing new. In fact, it’s been advocated already for years. Even Google themselves advised others to self-host fonts in their Google I/O ‘18 talk about web performance.