I used to think the same way. But gyms vary widely in quality and culture. And you can go at your own pace, nobody is going to make you do more when you're ready to stop.

I personally would prefer to just lift. But unless you're pretty lucky, or are willing to invest the time and expense, you won't have access to a gym with decent equipment. Since convenience is a huge factor in lifestyle choices like working out, you need to choose amongst the activities that are close to you. Once I graduated from cardio at Planet Fitness, the only place to go really is Crossfit.