Is it a bad idea? That's not really the right question. The better question is "Do I have anything substantial to gain from using an LLB?". The answer, in my opinion, is no. For one thing, it hides things. You can't see what's inside an LLB unless you open it. However, under Windows an extension is available when you install LabVIEW that allows you to view the contents of an LLB in the same way that XP allows you to view the contents of a ZIP file. The basic premise around LLBs was to get around the 8.3 naming limitation that Windows used to have and to provide cross-platform naming compatibilities. There is no 8.3 naming limitation anymore, and the cross-platform naming issue can be solved by the "let's not use any funny characters in our filenames" rule.
How to do what you want depends on what you're starting with:
If you don't have a project, open the top-level VI of the application you want to copy to another computer. This will make sure that all subVIs get loaded into memory. Then, from the file menu select "Save As...". In the dialog box select the last radio button. You will be prompted for a folder name to which to save the hierarchy (in other words, the top-level VI and all its subVIs). If you wish, you can create an LLB by clicking the "New LLB" button.
If you have a project (and this is the better long-term solution), create a new source distribution build. With the project open, right-click on the "Build Specification" item in the project explorer. Select "New->Source Distribution". Specify the target directory and you can just click "Build". This will copy the top-level VI and all associated subVIs to the new location. You can then save this build specification so that you can run it each time you make changes.
As for the project, do you have to track down each VI and save it to the project? Not really, though it's easier to understand what the hierarchy is if all the files show up in the project explorer. If you were to open the top-level VI, and then select "File->New..." and select "Empty Project" you will be given the option to add all open VIs to the project. Note that if the only VI that you have open is the top-level VI, then the project explorer will only show the top-level VI. You can then right-click on the "Dependencies" item in the project explorer and select "Refresh". This will populate that tree item with the names of all the subVIs. You can drag the files to be listed right under "My Computer" if you wish.