I shop at "the real Walmart" occasionally, but I go to the smaller Walmart Express more often. It's small, sized like a regular grocery store, so it's easy to get in and out quickly. The prices are roughly the same as Aldi's, but the selection is different. Every store has its own strength, and Walmart's is simple, old-fashioned foods; for example, dried beans, flour, etc.
I agree that Walmart (or Target) is attractive to people who want/need to do all their shopping in one place. My grandmother loved Walmart because she only had to get in/out of the car once, yet she could buy her groceries plus something from home goods and whatever else. The same could be said for parents with small children and people who don't have their own cars.
What's the difference between Walmart and Target? Mostly staging. Walmart just slaps stuff on the shelf and says, "Here, come buy it", whereas Target clearly has a team of marketers who put together new and trendy decorations for the front of the store -- and since they use the same stuff in every store, it's a bargain. They also are more cued into trendy colors and styles, though their quality is no better than Walmart's.
Finally, I agree with the poster who says, "Yeah, some people do need that cheap stuff." Yeah, when I was young and poor, I had trouble affording Walmart stuff. At that point in my life, the choices were this or nothing, so I was glad to have their cheap towels, etc. I'm glad not to be in that situation any longer.