I am actually thinking about the same thing so I can explain the rational of buying the primary residence first. The primary residence usually has more “quality” requirements and it justifies a higher price point (because you don’t have vacancy issue to deal with).
If you buy an investment first (e.g. condo), then you are hoping that the price will continue to drop for you to upgrade soon. Otherwise, you will be stuck in a house that you don’t like.
Investment comes after current consumption (which essentially what primary residence really is). If after I buy my primary residence, the price drops to a level that is so attractive, then I will invest in the property market. Otherwise, I might as well seek other investment opportunities.
I am not familiar with any tax/interest-rate advantages. So I hope someone would enlighten me what these impacts are.