That is what it is called in Kamigata (the Kyoto-Osaka region) because the phrase "Benben," an onomatopoetic expression of Gidayu shamisen (shamisen used for Gidayu when reciting dramatic narratives), is uttered as an interjection.
合いの手として、「ベンベン」（義太夫の三味線の音色に由来）と入れることから、上方ではこの名がある。