| | Re: Why are DNA primers used in PCR but RNA primers used in DNA replication?
I believe your question is partially incomplete or wrong. Neither process requires any RNA primers.
What do you mean by DNA replication? If it's a natural biological process in the cell, it doesn't involve RNA primers.
If it's a synthetic process in the lab, then DNA replication would likely be in the form of amplifying specific regions of DNA. And well, DNA primers are more stable than RNA in vitro and easier/cheaper to synthesise.