First and foremost, cylindrical weights are often cheaper. If you are someone who is trying different brands of risers, they’re also universal. You can easily move them from your starter Galaxy, Kinetic, or WNS bow to your flagship Hoyt then to your Gillo. So you buy them once and they last effectively forever.
Secondly, they work well. The center stabilizer bushing is generally the best place to start adding weight if you want to move the bow’s center of gravity towards the target and the ground. That’s why stabilizers go there, after all. Personally, for a barebow riser, I think the weight is best added a couple inches below that (see where Demmer’s giant, offset disk’s center is, which is close to where Hoyt’s pro weight sits, or the Gillo blade, or where basically everyone puts their front hammers). But that can be approximated with weight in the middle and bottom bushings.
Hoyt’s pro weight works well, but the minimum configuration is 40oz. Their regular plates don’t quite balance the riser on their own. So traditional cylindrical weights work well for anyone who doesn’t want a very heavy bow. It’s noticeably worse on the 27 than the 25.
Gillo’s hammers are the best system for balancing a bow how you like (although they’re just a little too long to make the full range of rotation WA legal on a GT). But pre-dampeners being legal, they did add a noticeable vibration to the bow. That’s an easy fix now, but many archers still prefer a simpler solution. The second best choice is the blade weight, although that is a “love it or hate it aesthetic” for many. So then you’re looking at configuring weight covers or cylindrical weights. The weight covers have so many options that cylindrical weights seem like a safer choice if you don’t know how much weight you need. Many archers will use them to figure out how much weight and how they want the riser to balance before investing in riser specific options, and a fair number will decide that since they got their bow how they like it already, they don’t need to purchase anything else.
Having used the Gillo weight covers (brass, steel, and aluminum), the hammers (stainless and aluminum), the Hoyt Pro weight (aluminum sides), and Yost weights (16 and 11.7 oz), I have to say that while the Gillo hammers work the best and are my favorite setup, the Yost weights were the best investment because I could use them to experiment on a variety of risers. Granted, at their current prices, Yost weights aren’t cheaper than a dedicated solution.
I got a Gillo bow because I like to tinker, and the weights let me do that. I can be as picky as I like (or, more accurately, as I can afford). But for archers looking to spend less, and who don’t have the option to try different weight kits before investing, a stack of stainless steel cylinders they can attach to the stabilizer bushings are a great choice.