Some older cannondales came with a 24" wheel...
Honestly, for me, If it serves the purpose of riding offroad (with the exception of CX bikes) it's all good.
24" wheels; Good.
Converted old klunker; Good.
Drop bars; Good.
Ridden in the dirt; Gooooooood.
I guess the key is knobbly balloon tyres*
*although an MTB on slicks is fine too!!