I appreciate disc drag reels for saltwater use. Species like permit and tarpon and others are extremely strong and make fast, long runs. In freshwater, I might use a disc drag reel for Chinook salmon. Chinook can be large, and playing them with fly fishing tackle can be a lot like work. I fish for fun, not so much for work.
I use nothing but spring and pawl reels for steelhead fishing. First and foremost, I'll again register my complaint about the term - now even used by weak-minded manufacturers - "click-and-pawl" reels. I have many such reels, mostly Hardy, and I have examined every part on them. There is a spring, and there is a pawl. The reel makes a "clicking" sound when the spool is turned. However, nowhere on these reels is a part that is called a "click." It just isn't there friends.
Now then, I can find no disadvantage to using spring and pawl reels for steelhead and trout fishing. The spring tension serves mainly to prevent spool over-run and provide minimal drag. I apply infinitely adjustable drag by pushing one or more fingers against the remaining line on the reel spool. I can apply anything from light pressure, or bring the spool rotation to a dead stop.
I stick to this time-tested tackle for a couple reasons. It's what I have and enjoy. The other is that I have a number of fishing friends who own and use high quality, very expensive, name brand disc drag reels that can stop a bus. They can, that is, when there are not being returned to the factory for some repair or other. I never have to return one of my spring and pawl reels to the factory. With an occasional cleaning and application of oil and grease, they function reliably for a hundred years and more. What's not to like about a product so good in this day when most manufactured goods are intended to be used and then disposed of?