See, I would class bean salad as the level up from traditional meal prepping because it solved a bunch of problems that I had with meal prepping
Sensory issues - I know that this is personal to me and some people might have the same struggle with the bean salad, but I can't deal with the texture of reheated meals, I can use frozen ingredients or processed frozen food like pizza or fish fingers, but the texture of a reheated frozen meal is never right
Cooking time/effort - If I can't be arsed to do anything, I can't be arsed to watch a pan, it's just as much effort to throw together a gochujang* or tuna pasta**. This also goes for the prep end, I find chopping a few veggies and draining some beans easier than watching a pan.
PDA - If I have prepped ahead of time, I might decide that I don't want it, especially if I feel trapped into eating it, and the benefit of the bean salad is that since it takes no prep, if I start to feel like "I don't want that", I can have a small spoonful, knowing that I can put the rest back if I really don't want it, before it can turn into a meltdown. Usually I start to actually want it once I start eating, but if I need to wait for it to heat up, I'll have a meltdown in the meantime.
Portion sizes - Prepping meals only works if you want a full-blown meal, the good thing about the bean salad is that it can work as a snack as well. You can decide how much you have when you dish it out, it wasn't decided ahead of time when you made it.
*pasta in one pot, and pre-diced frozen onions, garlic cube and veg mix of choice in a frying pan with some sesame oil, add some pre-diced panchetta or some sausage meat (you need to break this up with your spatula as you go) to the frying pan once everything seems unfrozen and starting to cook, and then add some gochujang and some tomato purée when it's starting to look done. Once it's all cooked, take the frying pan off the heat and add the pasta with a little of the water (I just spoon it out with a big plastic spoon so some water comes with) and mix it together before serving
**Even less effort than the gochujang pasta, just cook some pasta and throw in some pre-cut frozen veggies that do well boiled in with the pasta as it's cooking (I use a peas, broccoli and cauliflower mix - they typically take less time than the pasta, so I throw them in later). Once they're done, drain them all and then return them to the pan (off the heat) and add a tin of tuna and some mayonnaise and some white wine vinegar or some sriracha, and I usually add garlic pepper to everything.