Alicornutopia

Once you’re past the dangerous part of learning magery, and no longer randomly miscast spells, can you still deliberately miscast them? Is there any reason to do this except for a delayed painless suicide?

You could but there's generally no reason to; depending on the magic you're using, unstable spells might sometimes be dangerous to people nearby or have other specific effects, but if you can do that with a miscast you can do it with a regular spell, so that's probably not ever useful.