Yes with bitcoin earning we can buy land but if we sell land for buying bitcoin then i think its not a good idea because there is a Fluctuations in the worth of bitcoin but the price of land either remain same or increase as the time passess. We should also think about risk related to the earning mechanism as bitcoin can provide huge profit but there is also some risk with it whereas in buying land we don't have any risk issue.
Everyone will think differently but am agree with the success of bitcoin but for profit we have to wait for years after that we still have no guarantee that what will be outcomes of our investment. If there is extra part of land which is not used for the purpose of building a house then it can make a sense to sell land and buy bitcoin but if a person is on rent then selling of land does not suited well.
If you already have land I think it would be better to use it in other terms of investment like opening it up for rental spaces and things like that than selling it just to use the money to invest in Bitcoin, cause having land here in my country is much more valuable than a 1 BTC. Bitcoin investment is actually good especially if you have already accumulated numbers of Bitcoin for years, but in the current value of Bitcoin in the market, I think it would be too pricey where the plan is to buy low and sell high. You could expect a return on investment maybe for years, or even profits cause we are not still sure how far Bitcoin will reach in the next few years. Personally, I would be proud to own land, it's like saying you have 1 Bitcoin in your hands.