Bitcoin is just money. The only comparation or correlation between agriculture and bitcoin I could think about is the same when we talk about fiat and agriculture: you work as a farmer, grow your crops, sell it and are paid. So you use part of your payment to re-invest in the land and keep this cycle of work going on. You could do the same with bitcoin, instead of using fiat. Actually I think that is all and the same is valid for any other profession.
I agree. You have to grow what you planted. In agriculture, sometimes you have to risk and believe that the seed you buy have to germinate 100% to avoid loss. While in bitcoin, you are 100% sure that it is legit and what you have to do is make sure that you trade for the right time. Both are giving you profit when you take good care of them in your hands. In agriculture, you make sure to have harvest everyday to eat while bitcoin can be hold when it doesnt grow for the moment.