Have you considered the implications of hardware failure on uptime? And where the cost to maintain a physical hardware will come from? What about scaling requirements?

I'm not a network engineer, but I've been involved in the corporate argument of Cloud vs On-Prem. hosting for years now. The costs always come out better for Cloud when factoring in other indirect costs like facilities and labor.

Granted it's always been on the scale of hundreds of millions to billions of dollars, and I haven't run the numbers on smaller requirements. I just wouldn't want to expose additional points of failure in return for slightly lower monthly costs.