Steve Jones notes the issues around rebuilding tables lacking clustered indexes:
What about adding a clustered index and dropping it? Nooooooo, and again, I learned something new. This causes two rebuilds of the non-clustered indexes as they are rebuilt with the cluster addition and then rebuilt when the table changes back to a heap (to get the heap locations). That’s crazy, and certainly not what we want.
Also read Matthew Darwin’s comment, as “Don’t do X” usually has an “Except when Y” corollary.