Yes, they really are some kind of an allroundsolution because - like terminals - they can be used always everywhere. Crates look cool, vary in look and behaviour and are easy to build, what else would a detail-addicted want for his latest map? :) For sure, the original standard crates from Doom itself might be a bit outdated, because they have already heavily been used in E2M2 and other original maps. That's when I recommend the wooden crates from Final Doom TNT Evilution, some shawn-crates from Nightmare's texture packs and also these beautiful Strogg-Crates from the Quake Texture Packs.
In shot number one I have just a very small demonstration of the usage of crates. As you can see, they different sizes of crates combined together look brilliant and now imagine: You could place this bunch of packages in every sort of style or map, it would always fit in some way :) Another good tip I didn't incorporate yet in this wad is the usage of a platform below the crates (just as a border once again), which might be helpful if you want to put crates in hellish maps.
Summary: The combination of different sizes and colors of crates is one of the secret-recipes for persons who lost their creativity concerning "senseless stuff in senseless rooms", and thx to the resource-creators, we have a big choice regarding the crate design ;)
Extra-Buildtime: "1-10 minutes" (depends of complexity of the crate arrangement)