This is a still photography site, so there might not be a lot of people here that can help you with the video work. The device you are looking at looks a lot like a SteadiCam rig. I have not seen anything like that used in wedding photography; it seems more for commercial production where the cameraman has a lot of space to maneuver. That is not a situation you are likely to find at a wedding.
Shoulder mounts are something I have seen used at weddings. The quality of some of the low end units in the price range you are looking at look a bit questionable. I have never shot either a SteadiCam style rig nor a shoulder mount, so cannot comment. The type of video I shoot means I tend to use a heavy duty video tripod; that is not going to be what you want to use in a highly fluid environment like a wedding.
A shoulder rig looks like this:
https://www.bhphotovideo.com/c/produ...ulder_rig.html RedRock is a well known and reputable brand for this type of equipment.