By the time you get a Rpi 4, a decent power supply and an external SSD, it's usually around the same price as a mini PC which you can get with a 7th/8th/9th Gen i3 or even i5 with everything included.
I get that the Rpi will use less power, but I imagine many people will be like me and have it overclocked to 2.1ghz, and my heatsink was pretty warm all day long.
I've recently picked up a Optiplex 3070 with a i5 9500t for $120 and bought 32gb of ram off ebay for another $40. Considering a Rpi 4 is going for $100 on eBay, it's not a bad deal at all.