(disclaimer I guess I own a company that offers VPN services, it's like ~1% of revenue though). I think this seems like a bit much. I'd love Firefox to double down on building a great browser, rather than getting into Pocket, VPN, a Phone, IOT, etc. Sure, a VPN can be really helpful when you're on sketchy open wifi, or other adversarial network conditions. But you're still trusting someone to handle your connections…
Can you actually check if a VPN provider logs data? No, but Mozilla certainly has more sway than I do.