What is a benefit of low SWR?

Standing Wave Ratio (SWR) is a measure of how well the impedance of the antenna and feed line match the transmitter. When the SWR is low (close to 1:1), it means nearly all the transmitter's power is being successfully transferred to the antenna and radiated out into the air as an RF signal. If the SWR is high, a significant portion of the RF energy is reflected back down the feed line toward the transmitter. This reflected energy results in signal loss because it turns into heat in the coax rather than being radiated by the antenna. Distractors like "reduced television interference" or "less antenna wear" are completely irrelevant to SWR. A perfectly matched antenna can still cause interference if transmitting on the wrong frequencies, and antennas don't experience mechanical physical wear from standing waves.