I would never buy gold as part of a growth investment strategy, but I own some simply as a diversification/hedge.- As for crypto, it's just a speculatory investment for those who like to gamble. 

Diversification in Real EstateInvestors and homeowners today often have diversified real estate portfolios.

I need the cash flow, the underlying assets, and then the diversification of assets(real estate, agri, energy, equities, fixed income, alt investments).

You will also learn from others which operators they like or don't like, which asset classes are going well, diversification strategies, standard terms and more - and most of all you will have other like minded individuals to consult with who are on a similar journey.  

I kind of look it as similar to diversification on the market.

But for diversification and end of year tax bene's they served the purpose at the time..

Some good metrics to help determine markets and submarkets can be; rent growth, income growth, job growth, population growth and job diversification.

Diversification is key.

This can allow a person to get much better diversification protection across geographies, asset types, strategies, investment subclasses etc.

@Jonathan Oh I understand what you mean in terms of diversification.