Medical cannabis v conventional drugs?

If you were to have an incurable untreatable condition that it didn’t kills you but got worse over time and gave you chronic pain everyday and the alternative to cannabis (which is illegal in most countries) was morphine (which is regularly available on prescription legally) keeping in mind that both drugs are regulated a on schedules and classifications which put cannabis as a class B and morphine as a class A which would you opt to take keeping in mind the adverse reaction and after affects of both….... what would we base our decisions on would we look at the legality side of it? or adverse reactions and after affects?