> What happens when this runs on 100K rows against a service some guy stood up as a weekend project? Now what happens with 100 people hitting that service?

Then they complain to Microsoft, who helpfully suggests the product they should upgrade to. This has always been a strong spot of Microsoft's. "I see you've scaled beyond the capacity of [Product A]. Well, fortunately for you we have [Product B] which can handle it, with a nice import wizard to get you started painlessly." It typically goes Excel > Access > On-prem SQL Server > Azure.

This sounds very negative and I swear I don't mean it that way. It's a great sales tactic if you offer products at every level of scale.