I have just got hold of some engraving bits, a gift to me from a friend

There are two types, 0.2mm 30degree angle and 01.mm 90degree angle.

Question is - what is the suitable use for these?

My guess is the 90deg ones are only for very shallow cuts but the long 30deg ones? Very shallow cuts?

Both are solid carbide, I got 10 of each.

I could find uses if they are indeed suitable for engraving stuff