When you take a walk is that simply recreation or is it exercise? What about when you go kayaking? Canoeing? Bicycling? Swimming? Gardening?
Anything we do physically may be beneficial if it puts a demand on our bodies. That stimulus creates an automatic response. And, since the body's response to healthy stimulus is to strengthen the body, to empower the body to do what we have done more easily, the response is usually healthy and supportive of an active lifestyle. But are your activities providing you a helpful stimulus?
I have pointed out that doing pushups is less advantageous than rowing. Pushups use a limited set of muscles. We do them briefly (not for 30 minutes). Doing pushups rarely gets our pulse up or causes the breath to become deeper for a prolonged period. Doing pushups differs from rowing in these ways and, as a result (I would say), is less positive for health.
At the same time, when you or I hold our body in position to do pushups, we are essentially doing core work at the same time. That is positive and supportive of overall bodily health in a different way than the muscular effort to lower and lift the body. (See section of the book on core work.)
So if we garden or kayak and do not break a sweat or breathe more deeply, it may be that what we are doing during that physical activity is not as efficient or as productive for our health as rowing the same amount of time. But it likely does have positive benefits. What are they? Are you happy with the results as well as the process (what you are doing)?
How do you decide what to do? To the extent you have time, do it all. Do the chores and simple things that provide enjoyment and some benefit. And then row each day to round out the benefits. Spend some time breathing more deeply and watch how your rowing supports your other activities over time and perhaps the reverse will be true, as well.