I wouldn't say it's a waste of time, but it depends where you want to go in life. If you prefer the pure mathematics side, with it's abstractions, more academic focus, and are seeking a career in academia, finance, insurance or quantitative analysis, cryptography or security, rather than say the more typical engineering choices above, then it isn't a waste of time. What I'm saying is that it isn't an engineering degree, nor will be respected as one in engineering circles. It's a maths degree, with a bit of engineering tagged on for interest on the side.
So yes, I agree with your above statement. it is not a good degree if you want to do engineering, but for a more mathematics based focus - sure, it's fine.
Just make sure that you realise that an engineering degree will offer you plenty of mathematics options, AS WELL AS engineering ones too. A mathematics degree, even one "with engineering" does not.
I could have chosen plenty of additional mathematics modules in my degree too, if I wanted a more mathematical focus, and I'm sure that is the case for the majority of engineering degrees. It's just more applied mathematics - problem solving, by using the theory to do something useful, rather than understanding every nuance and consequence of that theory.