I just bought $40 bluetooth earbuds that required RTFMing to pair, don't hold the pair between workouts, take a minute to perform the ritual, and use friction to anchor themselves to my ear so thy fall off the moment I start sweating. Oh, and they need to be recharged.
I have similar stories for every single bluetooth device that I have ever tried, which amounts to probably a dozen peripherals and half that many hosts. I've had fleeting moments of "it's magic" to punctuate the sea of crap so I'm fully on board with the potential of the technology, but it has continued to mature at an obnoxiously slow rate.
Your bluetooth speaker setup works great for precisely your scenario - the speaker is paired with one only device.
It gets wonky if that single speaker has paired with multiple devices before. For example in a home, where you've paired it with your laptop, phone, iPad, etc. Try it out. Audio will cut off sometimes suddenly when it decides to switch pairing partners as another paired device appears in range.
I have a Sony bluetooth headset and it's amazing. It was around €65, lasts 40 hours of use (so charge once a week- every 2-3 weeks depending on usage), pairs with 3 devices and does it very well. I often move to another floor while having them on (construction work) or go out to the shed while the iPhone is in the bedroom on a charger, and it still works 10 meters in the yard. Best thing I've ever purchased, so there are good Bluetooth solutions.
I have similar stories for every single bluetooth device that I have ever tried, which amounts to probably a dozen peripherals and half that many hosts. I've had fleeting moments of "it's magic" to punctuate the sea of crap so I'm fully on board with the potential of the technology, but it has continued to mature at an obnoxiously slow rate.