To save your time and let you the way to create symmetrical buildings faster and more accurately, «Build with Cubes» have a Symmetry Mode. When you place one cube it could be mirrored 2 or 4 times depend on way you choose. Moreover you can change the symmetry pivot to build with blocks a lot of symmetrical constructions.
Use Fly Mode to fly around and control your construction from different angles. There is no restrictions for placing a blocks - you can add cubes from any available point, it does not matter whether you come close to it or flew away from it by 100 kilometers.
You can save your project to local slot and open it later for editing. Also you can publish your work to app's collection/gallery and open other projects to change it and add some creativity.
When you publish your work, application create a web-page with layered schematics of your construction. Share your construction with friends through social networks! Also you can create schematics .NBT file of buildings.