FPGAs are widely used in low latency trading. Most market data feed handlers and order passing adapters are done in FPGAs today - they offer better latency than software solutions and processing time is deterministic.

One example of a company offering something like that: https://www.enyx.com/

It highly depends on what you're doing, but in trading there is very often a direct reliationship between latency and how much money you can make.