What is the benefit of making voltage measurements with a true-RMS calculating meter?
Why RMS (root mean square) is the equivalent DC heating value of a waveform. Ordinary average-responding meters actually rectify and average the signal, then multiply by a fixed factor (about 1.11) that is only correct for a pure sine wave, so they misread square waves, pulses, SSB audio or distorted AC. A true-RMS meter squares the instantaneous samples, averages them, and takes the square root, so it reports the correct RMS value regardless of waveshape.
Watch out Converting to phasor form is tempting because phasors are drawn with RMS magnitudes, but a phasor also needs phase information that a single RMS reading does not supply, and phasors only apply to sinusoids anyway.
True RMS = true for any shape. Average-responding meters are only calibrated for sine waves.