I feel that you aren't getting any responses as your question is vague and not really clear. Are you wanting to get a 24 gallon nano aquarium, that has an overflow? What type of "built in filter" does it have? I wouldn't see why you couldn't use sand substrate unless it has an undergravel filter. As for plants, it depends on the lighting and depth of the tank. As for "being worth it," what exactly do you mean? Would you be buying it? If so, used or brand new, how much, and what do you plan to keep in it? Generally, nano cube tanks are overpriced, and for the cost of a new 15 gallon or something nano, you could get a standard 55 gallon set up. If not being able to see the filter and stuff is important to you, then it may be something you want to consider.
