I think 'gambling' really depends on your intent when it comes to bitcoin or any asset. For example, you could buy a house with the intention that it is an investment that you will make better through your own hard work and dedication. You will have that house for your family and maybe even their family. Or you could buy a house because you hope to profit off the rapid increase in property values in that area. If you were strictly religious, that might be too close to gambling for comfort.