A lot of people don't like putters, especially new players. The deep rims are hard to get a comfortable grip with, especially if you have been throwing high-speed drivers. The transition from the large rim and low profile to the small, deep rim requires a different grip for most players. So getting used to them takes some time and practice, something many people don't or can't do. So, they end up putting with something else that feels more comfortable.
However, pretty much 100% of people I know who have taken the time to practice and develop thier game uses a putter. The larger profile hits and sticks in the chains better. They are less LSS and easier to put on a straight line with a putting motion. They don't have a ton of glide, so they leave you with a decent come-back attempt when you miss. There really isn't a downside to putting with them, other than the comfort factor. Once you figure out the grip, that is no big deal.
Personally, I hated putters for years as a casual player. Back then there was no such thing as putters, everything was a "driver" or an "all-purpose" disc. Most of the discs now considered putters were "all-purpose" discs, which is a better term for them since they are good for putting, approach shots and short to medium drives. Anyway, I hated the way they felt in the hand. It took a couple of years to get used to them. However, back then discs like the Aviar and Phantom were the "go-to" discs for most of the players I knew, so I kept trying to work with them. Once I figured out the grip, it was all good. That was 15+ years ago, and I never really think about it. The Aviar has been a staple of my bag for so long that I forgot that I hated the blasted disc when I started.
