He's partially correct.
Tables without clustered indexes (known as "heaps") are useful for staging tables for bulk loads. These staging tables are not your final tables. For example, the data you load may be data you already have so you only need to find new, changed and deleted records for your final table.
And yes, it is an overhead to recreate the clustered index. When dropped, data will be allocated wherever. When rebuilt, it will rearrange data on disk.