They are great heavily supported Linux machines though. They work out of the box gorgeously with numerous distros and being usbc is nice. For $100-200 for a mint condition model, it isn’t so bad.
Since the release of Touch Bar based Macs (which contain apple silicon) this has not been the case. The Macs that are well supported by linux and work very well were abandoned long time ago.
It was the first mass market SoC hardware test of their new Mac chip design and it seems it was also to prep macOS for the M line. The level of control Apple gave it makes repair and refurbishing very difficult without Apple’s authorization.
T2 Overview PDF https://www.apple.com/jp/mac/docs/Apple_T2_Security_Chip_Ove...
Would the M* be much better? Obviously, but that's not (yet) in the cards.