Well the seed is what contains the most amount of bioavailable nutrients, not the plant itself. The hemp seed is what is being processed and sold as a nutritional supplement. Yes it does in fact contain omega 3 and omega 6 fatty acids and in the correct ratio. The ratio is what plays an important role. Fish oil does not have the correct ratio of omega 3 to omega 6 and Mercury, Chlordane, Dioxin and PCBs are toxins potentially ingested by people who consume fish oil.
Hemp oil is actually plant oil from the foliage and stem being processed and then added into corn oil, vegetable oil or coconut oil. Read the ingredients. That is where those omegas are coming from. For certain products I use MCT oil but for another reason not associated with this conversation.
I have a line of supplements coming out soon on my website but still in the manufacturing process. However just like tainted fish with pollutants so can the plants be with heavy metals, PGR (plant growth regukators), systemic pesticides and fungus and bacteria. It comes down to the farmer and how he grows. Too much to say as it all relates and im in the field.
Short answer is yes, it is better. Long answer, be careful what you buy just like all things.