This is one of few dishes of the traditional German cuisine that are vegetarian. I don't think it's a German dish only, it's common in Czechia, and in Poland as well I think. The simplicity of this meal is almost proverbial, and in my view that's an advantage. It's also a very price-friendly thing to eat, you can pretty much cook for three or four people while spending what you'd pay for one coffee at a non-fancy place.
In Germany, the potatoes are typically boiled without skin in lightly salted water for this dish, then salted and buttered and served hot. The eggs (the standard is one or two per plate) are fried in a bit of oil or butter and simply flavored with salt and pepper. The only thing slightly more adventurous for the beginner cook might be the spinach. For this dish, cream spinach is typically served, prepared with onions and/or shallots, cream, nutmeg, salt and (white) pepper. You can of course buy cream spinach deep frozen, which is no less healthy, and makes the dish ridiculously simple to prepare.
Some people don't enjoy potatoes, spinach and eggs much as a child, but then warm up to the dish as an adult. I personally think it's outstanding in the combination of mild, but hearty flavors that are slightly similar, but also complement each other well. Potatoes are a delight with butter or margarine, and you don't need much of either. The cream spinach can also be used as a sauce to dip the potatoes in. The fried eggs are a nice little extra to nip from in between, and with enough black pepper they can add a bit of a sting to the meal.
Potatoes, spinach and eggs is a very filling meal without being all that heavy (as long as you're not too generous with the butter and cream). You won't need to eat much. The potatoes will keep you full for a long time, and while perhaps not everybody would count them among their five a day, you can definitely count the spinach. The eggs add the quarter of protein recommended by nutritionists.
All in all, this dish is great in all categories, be it ease of preparation, cost, healthiness, or taste.