joint: In a joint some people have weed and tobacco,and the tobacco can cause you:lung cancer,larynx caner ,mouth cancer , esophagus cancer and many more cancers.also in a joint you have paper which lets out bad fumes which you shouldn't breath in .
bong : In a bong you have water and cannabis/marijuana which can save cancer and help it with many ways . with a bong you basically vaporize just weed which contains THC crystals which are off the weed and what makes you high. With a bong you don't smoke the paper which is better for your lungs .
If you have any ideas about which one is better leave a comment down below .