angular cli and Internet Explorer, what is the cons of uncommenting polyfills.ts

Question

I had the same issue as in Angular4 Application running issues in IE11 and the solution does solve the problem at hand, but I could not figure out why these lines ( IE9, IE10 and IE11 requires all of the following polyfills ) were commented to begin with ? What are the disadvantage of un-commenting the section in polyfills.ts

Answer 1

I believe the disadvantage would be that the bundle size becomes larger.