Personally purchases go in order of priority: watch > jewelry > bags/RTW
To be very honest, while I am all for buying what makes your heart sing, when it comes to watches vs jewelry, I will take into account how much value the item can hold and resale value. And that is the main reason why I chose the rolex over the ecrou. There are just some things that I can't get out of my head and that's how well a rolex can hold its value relative to a piece of fine jewelry.
On the other hand, I do understand the maintenance and minor annoyances of an automatic watch. And if you're not wearing it daily, it's a bit annoying to keep on setting the time and winding it. I rarely wear my automatic watches anymore even though I do love them for what they are, their mechanisms, and that ticking sound.
My daily watch is my Panthere and quartz is just so easy to work with. I actually find myself using it sometimes, which is surprising since we have our phones. It can be a tad more fuss free to just turn your wrist to read the time than pulling the phone out of the pocket or purse, especially when I'm on the move or in a hurry. And it has come in handy when my phone is not with me or is charging somewhere.
But I also wear it for sentimental reasons, it is a wedding anniversary gift from my husband so I am always very happy to wear it all the time.
About the ecrou, I do really like it actually. It's not a piece I see often in the wild so my heart skips a beat when I see it! I like the clean and industrial design and it will match with your other jewelry very well. As a bracelet, I think it is a great choice.
Have you tried on both items with your daily jewelry pieces? If not, best go do so! It's one of the best ways to know if you love it or not.
Either way, at the end of the day, it matters what you love more! Please let us know what you end up deciding on. Good luck and happy shopping!