I made an impulse buy of an Android/Google Fit watch a few years ago because it was cheap (Fossil, less than $100, was latest gen at the time) and a one day sale. It's slow as shit, but it does everything I want it to do.
Heart rate is nice, but not all that essential IMO. No oximeter. No sleep monitoring (I have a CPAP that does that anyway).
I *only* wear it in the gym. I primarily use it to skip songs I don't want to hear, and quickly be able to look at my watch without pulling out my phone to see who is calling/e-mailing/triggering my front door camera/view texts. I just don't like being bothered in the gym and having to pull out my phone to see all that. Typing on a watch is unrealistic. If I'm somewhere on my way to/back from the gym and I need to buy something, convenient to use Google Wallet on the watch rather than the phone.
If the Apple Watch had a useful interface with Android (it doesn't), I'd be tempted to get one, as it is superior to the new Pixel Watch. Pixel Watch isn't there yet, it's first gen, I'm hoping that the next gen will be better. I'm very anti-Apple, because they lock you into their ecosystem and want you to pay for *everything*. Pixel/Android all the way for me.
A lot of your decision depends on so many factors it's hard for someone to tell you exactly what *you* should do. For me, it mostly comes down to how much you are willing to pay for the convenience of not pulling out your phone every time something comes in. Unless you have money to burn, I think quality watches are way overpriced (and I'm not hurting financially). I currently see no reason to upgrade, as although my watch is old, beat up, doesn't hold a charge too well, etc., it still does everything I need it to do.
Reviews by actual users are your friend. If you don't normally wear a watch, unlikely you will start doing so with a smart watch.