The click and the word do the same job
Both a clicker and a verbal marker exist to solve the same problem: bridging the gap between a behaviour happening and a reward arriving. Neither is inherently more rewarding to a dog, they're learned signals, built through repeated pairing with treats, that tell the dog exactly which action earned reinforcement.
Trainers who prefer the clicker point to its consistency, a mechanical click sounds identical every time, whereas a person's voice naturally shifts in tone depending on mood, environment, or how many times they've said the word that day. Trainers who prefer a verbal marker point to convenience, no device to fumble for, and it works even if your hands are full of lead, poo bags, or a squirming puppy.
When a clicker has a real edge
A clicker can be genuinely useful in a few situations: precision work like shaping a completely new behaviour in small increments, situations with a lot of background noise where a spoken word might get lost, or households where several people are training the same dog and want a perfectly uniform signal regardless of who's holding the clicker.
When a verbal marker makes more sense
If your dog startles at sudden sharp sounds, has general noise sensitivity, or you already have a reliable "yes" or "good" that's been used consistently, there's no need to introduce a clicker. Some dogs that are wary of a clicker's sound can even find it counterproductive at first, requiring extra desensitisation before it becomes useful, effort that isn't needed if a verbal marker already does the job.
Verbal markers are also simpler for everyday life. Recall training in the backyard, marking a moment of calm when a visitor arrives, or rewarding a polite greeting are all easier to mark with a quick word than with a clicker you have to locate first.
Charging either tool the same way
Whichever you choose, the process to make it meaningful is identical: pair the marker with a treat, immediately, with no expectation of a behaviour first, ten to fifteen times per short session. Your dog needs to learn "that sound predicts a reward" before the marker can be used to shape anything. Skipping this step is why some owners feel their marker "isn't working", the association was never properly built.
The bottom line
Pick whichever tool you'll use consistently. A clicker used inconsistently is worse than a verbal marker used reliably every single time. Consistency of timing and delivery matters far more than the specific sound you choose.