What is the drawback of STP?

As a keen observer of the financial and cryptocurrency landscapes, I must ask: What is the primary drawback of STP, or Straight Through Processing? While STP undoubtedly enhances efficiency by automating trade orders from initiation to execution, bypassing manual intervention, I'm curious to understand its Achilles' heel. Does it perhaps leave room for errors due to its reliance on algorithms? Or does it lack the flexibility to adapt to sudden market fluctuations? I'd appreciate a concise yet comprehensive overview of the potential challenges that STP might pose in the realm of cryptocurrency trading and finance.