Of course it all depends on the end result you want.
Aging for 3 days by leaving the steak in your fridge is OK and it may produce the flavor that one wants, but traditional dry aging is done for 2-3 weeks in special dedicated coolers in meat processing plants or in the restaurants.
If you leave a ribeye or a striploin open in your fridge for 2-3 weeks you would not want to open the door or have any food sitting there with it.
Also air circulation provides moisture release which is critical to developing dry aged flavor. The reason I used these bags is that it allowed me to dry age for 2 weeks and produced the same deep rich flavor as I enjoy in the upscale steak restaurants like Capitol Grill or Smith and Wolensky.
It all depends on the desired result.

If you just left the meat hanging in the fridge, would it not pick up odors from other foods in there?

Precisely, if you left meat in your fridge, it will pick up the odors and also release odors to other foods. With the use of this bag it does not happen. You can leave the meat in the fridge in a sealed bag for up to 3 weeks and it will dry age and not pick up odors from other foods. It sounds far fetched, but it works. Check out their site drybagsteak.com

Yeah, I am not buying any bag, especially when it is spammed. I do have a fridge in my garage that we usually use to hold excess soda and beer. I could easily hang meat in it and just leave the soda out.

thanks Jafo, was just going to post, this seems like an ad for the bag? hope your weekend is going well, very pleasant here!
looking for signs of spring.
Nan