First of all, it is fine not to see the use of an Apple Watch! Everybody has a different way of using devices and that is perfectly fine.
I might be kind of a weirdo, but to me, the Apple Watch is a device I had been waiting for for years, long before it finally was released. Why? “Designed by Apple in California.” Man, sometimes I really hated to read this slogan. Because it really showed on Apple products. Try to use an iPhone when it is rainy and you are outside. Try to use it, when it is freezing cold. Yes, there are ways, but they are not very nice. So, walking the dog in the winter or just being outside for that matter, sometimes I really wondered why there is no Apple Watch that enables me to control music, that uses Siri for interaction, that shows me notifications and so on.
Then the Apple Watch was announced (Series 0). I bought it on day one. I bought the next generation (Series 1). And I even bought the third one (Series 2). I skipped the Series 3 and I bought the Series 4. I cannot imagine not having a smartwatch.
These days, I am tracking my sleep, I track my walks and so on. I am no sports guy, but I enjoy the tracking. I do not know why, but I love it.
I use Things on my Apple Watch in order to mark tasks as done. I check my calendar. I control music and podcasts. I check my notifications. With Siri Shortcuts I use it even more.
There are days when I do not unlock my iPhone for hours, especially when being at work. The watch keeps me up to date and at work it is my primary Apple device to interact with (working in a PC environment that is).
If you use the Apple Watch just for fitness tracking, I would go for a (cheap) fitness tracker: