I need help with the below quesiton. I attached a link to data if needed.

Before choosing a linear regression, the winner described the following process

"I examined fitting a polynomial line to the data and using the line to predict future

values. I tried using first through fifth order polynomials to find that the lowest MASE

was obtained using a first order polynomial (simple regression line). This best fit line

was used to predict future values. I also kept the [R2] value of the fit for use in

blending the results of the predictor."

What are two flaws in this approach?

https://github.com/pankajksingh/LearnGit/blob/master/tourism_data.csv