In the serverless space - a few deciding factors we see people weigh (disclosure: Functions PM in Azure)- * Dev tooling. VS Code and Visual Studio 1st class tooling, including local debugging/breakpoints * Pricing. No API Gateway layer so these types of high load scenarios become significantly less expensive * Platform. Azure serverless is much more than just functions. Also serverless workflows (Logic Apps) and Events (Event Grid). Also enable multiple hosting models (serverless, dedicated, on-premises)