A timeshare/vacationing should not be thought of as an investment. No financial person would ever advise this. Ideally, in your budget you have a bucket for discretionary spending, which is where vacations and recreation will fall, and a separate bucket for investing, whether that be stocks, IRA, 401K, etc.
I've said this a few times before here, but here it goes again. FWIW, I am a "financial person".
Money itself doesn't have any true value. It's a piece of paper, or a number on a screen. The value of money is the goods and services it can be exchanged for. A well designed financial plan should be a strategy to allow you to purchase the goods and services that you need. If that has been taken care of, the next step is to come up with a strategy to purchase the goods and services you want. These needs and wants should be broken up into Short, Medium, and Long Term goals. As long as you are comfortable with your strategy to satisfy these goals, the rest is discretionary spending.
IMO, indexed ETFs are an investment. They are a tool used in my long term strategy (put X dollars into an ETF every paycheque), which is aligned with my long term goal of becoming financially independent (no need to work to support my lifestyle) by the age of 55. DVC is no different. DVC is a tool used to reach my long term goal of staying at a Deluxe Disney Resort every year for the next 35 years that fits within my budget constraints.
So IMO, DVC is an investment by it's very nature. Having said that, notice that I said that it is a tool used to reach my long term goal of staying at a Disney Resort every year. I could have said that my goal was to purchase DVC and then sell it in 10 years for 40% more than I paid for it. That too would be an investment, however it would be a poor financial strategy because it is not aligned to any specific goal. What would I do with that money in 10 years? Okay, lets change it up a bit and say that my goal is to sell it at a 40% gain to pay for my kid's education. Well now I have an investment that is aligned to a long term goal. This is really no different than my ETF retirement example. In both scenarios, I am taking money out of my budget today, and hoping that after a certain length of time I will see a specific return so that I can achieve my goal. If I were to buy a Disney stock today with the long term goal of selling it in 10 years at a 40% gain to cover my kids education, it would be the same scenario. Anyway you look at it, all three are investments.
Having said all of that, I would not recommend DVC as an investment if your goal is to sell it at a profit down the road, and you have no other means to achieve your long term goal. It is simply too risky of an option. I would also say the same thing about investing in DIS stock. Anytime you buy a single asset, there is a high level of risk. Anything could happen. This is why financial experts always suggest broad market investments. It reduces long term risk, while providing an acceptable, and easy to define rate of return that makes strategies easier to build. If you know what your return will be, you know how much needs to be invested.