Once calling land the best investment, it is not true to say that it is illiquid, your statement seems contradictory. The so-called best investment is a safe investment, the value is always increasing and has quick liquidity. I have never seen anyone have trouble liquidating land unless you sell it for too high of a real value. Land is certainly the best investment, but we shouldn't invest it all, diversity is always needed in the investment arena because the future is unpredictable.
I think all forms of investment have risks including investing in the form of buying land. Investment by buying land also has a risk value as you mentioned, namely liquidity. This means that if we want to sell it in a short time because we need money, the value will decrease. I agree with you, the fact is that the value of land will decrease because no one wants to buy it, meaning that we as owners offer other people to buy it. In short market demand, land location and economic stability are factors that affect the value of the land.
In-kind investment does look promising, but it's for the long term. If in the short term we will not get the expected profit margins. However, returning to each other's personalities, it should be underlined that the initial goal of investing is to pursue profits and minimize losses in the hope that the value of money will be stable.