Maybe I wasn't that clear in my post.
What i'm saying is that it's important to ascertain if there actually is smoke present, or whether it's just an alarm that's been activated. There many cases every year of false warnings so to initiate a full diversion and evacuation on a warning alone is not sensible.
If there was smoke, finding the source is important. While that is being done, a precautionary descent and diversion can be started. If it's serious, you're already on your way to a landing. If it is resolved, time to re assess your position and options.
Harry