In TimescaleDB, hyperfunctions are a series of SQL functions that simplify the manipulation and analysis of time-series data with fewer lines of code. They provide benefits such as reduced memory footprint, parallelization, and materialization in continuous aggregates. The `percentile_agg` aggregate uses the UDDSketch algorithm under the hood to calculate exact percentiles, while the `uddsketch` and `tdigest` aggregates offer more customizability with different approximation methods. These hyperfunctions enable developers to harness the power of time-series data, making it easier to analyze trends, understand system performance, and catch issues before they impact production users. By leveraging TimescaleDB's hyperfunctions, users can simplify their workflow, reduce computational resources, and improve the accuracy of their time-series analysis.