what are the advantages of pre-cast piles?

Advantages of precast or readymade piles are the following:

1. Precast piles can be cast well before the starting point of the work resulting in rapid execution of work.
2. Their construction can be well supervised and any defect detected can be rectified before use.
3. the reinforcements remain in their proper position and do not get displaced.
4. Precast piles can be driven in underwater.
5. The driving of adjacent  pile does not produce adverse effect upon the already driven pile.
6. They can be loaded soon after they have been driven to the desired depth.