Nails with felt tips ?

Ive been messing around with my nails as usually at school im the one who always has some groovy pattern on. Ive tried nail art, tips, marbling and many others but most of my nail art pens are running out and they cost me a fortune. The colour i want to use ( red ) is empty so i drew on my nail with a regular felt tip and coated it with a clear coat. it seems fine and looks perfect. I want to know if anyone else has tried this and what are the downfalls ? (if any) Because they need to look good :D