Lifting forces your body to work harder than just cardio alone. Why most suggest a combination if you want to do that. I just weightlifted to lose the bodyfat and gain body strength. Not that I didnt want to do cardio. It was I was seeing more results with the lifting. The gym did have a stairstepper and a stationary bike. Just never used them.
It is a myth that once you stop, all that muscle turns to flab quickly. You will eventually lose some muscle bulk, if you stop altogether but this takes time. However, you will stay strong. Only if you keep eating like you were lifting (to keep the energy up) you may gain some weight. You tend to eat more calories while lifting is why. However eating a good diet and watching your calorie intake, you can maintain your weight.
It is even suggested that taking off a week or two from lifting is fine if you have been going hard for six to eight weeks. As a "rest period" and then continue. There have been a couple of times I had to do this for family/business reasons and then went back. Just started out abit lighter than my last lifting routine showed and proceeded to progress from there. At this point, I am maintaining what I gained so far. I have tweaked my diet and now lost five more pounds. Maybe I will get to 165 afterall, finally lose all my stomach and see my abs
But in the meantime, just enjoy keeping my upper body strength.
It certain came in handy a couple of days ago. While driving home alone on a long windy rural state highway, a rear tire blew on my 79 Cordoba. I had to change the tire myself. Not near as tiring as the last time I had to do this last year after six months into my classes....nor as exhausting as when I had to do this, some years back, at 245. I carry a 2 1/2 lb hammer in my toolkit to help "break"/finish tighten the lugnuts with while using the "four way". The next day my shoulders were abit sore but it was a good feeling. So lifting has other benefits other than just losing bodyfat and better health.
You may find you need that extra strength in an everyday circumstance.
But in the long run, doing some kind of exercise twice a week is a very good idea. You are taking time for yourself doing something to feel good overall.