No it's definitely not a waste. It is the best possible value for gold you can get. Getting a premium tier 8 is a bonus but certainly shouldn't make you feel like you wasted your money as you do get a lot for it.
I bought a $19.99 box and received 4 tier 8 premiums I already owned. So I got around 40,000 gold. I also bought a $5.99 box and got two low tier premium tanks. I also bought a WoWP box and got some premium planes, and gold. Overall they were very profitable.