Land is considered as safest asset, no chance of volatility of prices. Means one time investment give more profit plus additional benefits. Risk of loss is very low, they used land for multi purpose like lending, housing, fishing or can convert it as resort or picnic point etc. Moreover its worth also increases side by side. These attractive ideas generate more profit for them. And the good thing is that these assets can transfer to their generation with increases value. Although land requires higher investment or or it requires long term return. Billionaires have the ability to bear both of them. Hence it is an assets that allows tye owner to expand their wealth over the time.
I largely agree with what you said. Land is indeed a great and relatively safe investment because it's a basic necessity that everyone needs.
However, unlike gold or Bitcoin, the value of land depends on location, market demand, and the economic situation. A plot in a prime area can run up big, while another one in an underdeveloped area can sit there for years with barely any price movement. Not to mention maintenance, taxes and other costs of owning rental property, plus market liquidity...
So land can be a great investment, but just owning it doesn't mean the price goes up on its own and you're automatically sitting on profit.