right, i should have led earlier with (1) exercise your body (musculoskeletal)
and (2) exercise your heart (cardiopulmonary), which is easier to digest and remember, as both are required for good physical fitness (you get digestive, lymphatic, endocrine, and other systemic benefits for free with this too).
the combination of these two goals should naturally lead to exercise with enough resistiveness for whole-body fitness (like basketball) without having to focus on each system separately[0], as you do with weight training, which primarily focuses on muscle mass. compound athletic movements naturally approximate what we do with our bodies daily anyway, which is what makes it intrinsically more holistic. you're right that walking by itself is probably inadequate[1] for musculoskeletal fitness, but 60+% of americans would benefit from walking daily. add swimming/cycling a few times a week and you're done!
the bigger point might be that good fitness doesn't require heavy equipment (ha) or a gym.
[0]: note that pain is a natural feedback mechanism that tells you where the imbalances are, to stretch, exercise, and/or rest more in that area.
[1]: it depends on what type of walking, yoga, or tai chi you're doing; for instance, competitive walking can be enough for some folks.