I wouldn't think it would be good for coding assistants, or things where character precision is important.
OTOH maybe the information implied by syntax coloring could make syntax patterns easier to recognize and internalize? Once internalized, perhaps it'd retain and use that syntax understanding on plaintext too if you fine tune it by gradually removing the color coding. Similar approaches have worked for improving their innate (no "thinking", no tool use) arithmetic accuracy.
OTOH maybe the information implied by syntax coloring could make syntax patterns easier to recognize and internalize? Once internalized, perhaps it'd retain and use that syntax understanding on plaintext too if you fine tune it by gradually removing the color coding. Similar approaches have worked for improving their innate (no "thinking", no tool use) arithmetic accuracy.