Some producers prefer the specific layout and "feel" of the version 10 interface before the major UI overhaul of version 12.
While newer versions like FL Studio 21 and 24 offer more advanced features, version 10.0.9 is often sought after for its: fl-studio-10-0-9-edicion-de-productor-completa
You can arrange an infinite number of audio clips, automation clips, and MIDI patterns without being capped. Some producers prefer the specific layout and "feel"