Until I had to buy one as an instructor in a local navigation course recently, I had never had or used a compass that had a "turn the screw" type of declination adjustment. I just adjusted for declination using the rotating bezel, which the Suunto A10 does have. It all boils down to how you want to mentally process this stuff. The ones with a declination screw tend to be heavier and cost more, which for a person just hiking on established trails strikes me as overkill.

For folks who for whatever reason need to establish a precise azimuth, perhaps to triangulate, it's a handy feature. More useful IMO for those that anticipate navigating off-trail.

For me personally, the (declination adjustable) electronic compass feature on my watch is what gets used, as it's always easily available. Perhaps not a comfortable truth for everyone, but the practical truth is that I pull out a "real" compass only if (a) just knowing where north is generally isn't enough in conjunction with "staying found" as I go along (rare), and (b) my GPS isn't along or I don't have relevant maps on it or a UTM grid on a printed map. Since my cell phone has a real GPS chipset, that means it's really quite rare today for me to dig into the pack to get my compass (one similar to the Suunto A10).

All that said, I do agree that it's important to know how to use a map and compass --- which is why what I actually do (vs. what a typical navigation class teaches) is sort of an "uncomfortable truth", I guess! All things being equal, I wish the particular class I helped with spent a bit less time on establishing and following precise bearings and more on navigation by terrain orientation and just "staying found".