Used business-grade systems are different to used consumer-grade systems though. Business systems are designed to last - some businesses use them in production for a very long time, and if a particular brand fails early, the businesses will switch to a different brand.
I've bought ex-corporate items, many times. Printers, systems, etc, etc.
But there is still a lot of potential oddities with a used system that a lot of people would not want to deal with.
No warranty, possible OS license issues, unfamiliarity with buying a PC on fleabay, etc, etc.
If the difference were $400 vs $200, that is one thing.
But $200 vs $170...not so much.
And for the difference between i5-6500T and i5-9500 ?
I could swap those interchangeably for my spouses system, and she'd never notice.
Bottom line - Both pathways have their pluses and minuses.