So imagine you have a big puzzle that you want to put together. But there are some missing pieces and you don't know what the whole picture looks like. All you know is that the puzzle is about a tropical island with trees, beaches, and palms.
Now, a tropical compactification is like putting all the puzzle pieces that you have in a certain way so that it looks like a complete tropical island. It’s like pretending that you have all the pieces and putting them together to make a complete picture.
But why is this important? Well, sometimes mathematicians have a problem to solve that involves tropical stuff, like tropical curves (which are like lines that have a certain shape in a tropical way), and they want to know what the answers would be if they had all the pieces of the puzzle. So they use tropical compactifications to help them figure out what the answers might be.
Just like how you can still have fun doing a puzzle even if some pieces are missing, mathematicians can still solve problems involving tropical stuff even if they don't have all the information by using tropical compactifications.