I had/have a similar one, although I think smaller container. It does work well for infusing marinades or if you are not skilled like me, just italian salad dressing into chicken breasts. I never think to use it in recent years, but is also because I never seem to think ahead for any meals either.
My Food Saver came with one I think. Either way I have one that worked fine the couple times I’ve used it. I usually speed marinade. Basically get a BIG gauge needle and big syringe from the local feed and seed, then inject marinade into whatever is getting cooked. If you have something even kinda chunky in it, like diced onion, jalapeño or dill seed; run it through the blender first.
I have one or two. It came with my vacu sealer when it was a promo for the quick seal thing. Does it work? eh. Yes. It does. But they are a bit more of a pain to cleanup as the lid is "reinforced" to prevent collapse. So I've basically used it only a handful of times, and now is used to store other stuff as its pretty durable.
I was listening to a foody podcast, and the chef put forth that you do not gain that much marinading. That if you cook with some of that marinade on your food you have the same result. Not sure I believe that.
However, admittedly, my palate discerns little difference between seasoning on the spot and an overnight marinade. I tend to slow cook, so how much does marinading gain me?
At this point, I tend to season up, add some apple cider vinegar, and into the slow cooker it all goes
The only difference is how tender the meat is: if I season and fry vs. season and slow cooker. Same base ingredients, same flavor.
It does work. But you don't need to do it for hours. Like a Marshmello expanding in a vac, the meat also expands.. soaking some marinade. However if your cooking low and slow, the pores of the meat haven't closed up, thus allowing your marinade to get in