The first difference is that CBD Oil from Marijuana, in most states, is regulated. You can't simply go online or run down to the corner store and order some. The government, as they do, have highly regulated it to the degree where you have to have paperwork to support your need for it and the people making and selling it have to have paperwork and rigorous procedures in place to meet the regulations required of the governments. It can be quite burdensome on everybody. And, as you might imagine, all those regulations end up costing people to integrate and it ends up adding to the final cost of the products.
The other main difference is that CBD Oil from Marijuana may, or may not, have a noticeable amount of THC, thus causing many people to get high or stoned when they use it. Most of us are not in a position to go around in this state all day. Personally, while I enjoy a good "relaxed evening" from time to time, I certainly do not want to go around all day, every day, high. I have customers. I have a family. I have friends. And, this is just not the way I prefer to go through my day.
Conversely, CBD Oil from Hemp is legal in all 50 states and it does not require any paperwork on the part of the purchaser. No prescription or medical card is needed. And, the people selling, while still having to maintain high standards of cleanliness and purity, do not have to document each and every drop and where it goes. So, while CBD from Hemp Oil still has a price, its generally much less expensive than that from marijuana. And, CBD Oil from hemp has to be below .3% THC, thus making it so low that people do not get any sort of "high" effect from its use.
Beyond that, the CBD molecule is identical whether it is extracted from hemp or from marijuana. No difference what so ever.
One thing that might be different is: CBD Oil from Marijuana is almost always 100% whole plant based. This means that when you buy it, you're also getting whatever other plant compounds were in the plant. Namely, this means the other cannabinoids and terpenes, phytonutrients, etc. Some CBD Oil from Hemp manufacturers, in an attempt to get higher amounts of CBD into their products, without raising the price, are only putting in CBD and not the other plant compounds. So, you have to make sure you are buying Full Spectrum or Whole Plant CBD from hemp when you buy these hemp products. If you don't you mind end up getting only CBD and missing out on the other great plant compounds like CBC, CBN, CBG and terpenes and so much more.
The overall benefit of CBD Oil from Hemp is that its less expensive, less paperwork, and still doesn't have THC so you won't get high.