I should easily attract good tenants.

Your equity in properties cannot be quickly or easily converted to cash, so it is not considered a liquid asset.While your net worth definitely includes both, one is not a millionaire until it's in a liquid state. 

If you want to do financing, they often expect a higher offer since there is a chance that the offer will fall through and the market may shift.Having cash on hand in general investment terms allows you to easily take advantage of good investment opportunities when they arise. 

You could easily run a little research to see what percent/how many travel nurses are being used by the local hospitals.

You might have won this one but you can piss away 25k very easily.

But this new property on the market has a guest house that could easily be rented.

A few years ago, you could find 1.0-1.2% pretty easily. 

However, Hud has a sequence for purchasing, easily circumvented when a buyer uses the listing broker as the buying agent as well.  

You can look to the sq ft requirements of a sleeping area per person and if that area can not be enlarged by rearranging the furniture for example, then you may say there is only the legal space for one person for sleeping.

That doesn't mean you shouldn't buy something illiquid, it means you need to consider the risks involved with investing in an asset that you won't easily be able to sell.