Especially for guitar, bass and other players who need their hands to play an instrument. This video explains how to configure the Boss RC-505 so it can be controlled via a FS-6 foot pedal. I just used it to "Start-Stop-Overdub" channel 1 & 2 but other configurations are possible.

Gear used in the video:
Boss RC-505 - https://www.thomann.de/gb/boss_rc_505...
Boss FS-6 - https://www.thomann.de/gb/boss_fs6.ht...
Stereo jack cable - https://www.thomann.de/gb/the_sssnake...