Noies cancellation versus safety first
The Momentum True Wireless 2 fit snugly into my ear, offering decent sound isolation from outside noises. There's also active noise cancellation (ANC), which does a decent job at filtering out the drone of road traffic, albeit at the expense of battery life.
This sounds great but is in practice dangerous in many real world scenarios: if you are anywhere near traffic, you must be able to respond to it and not drown it out! I recently got some Sony WI-SP500 to replace my Jabra sport, which I took to wearing in only one ear when out and about, and can confirm that the Sony buds do respond to external noises so that you can hear things like announcements, etc. Of course, if you're somewhere where it is safe and reasonable to want to cancel out noise (in bus, train, plane, airport, etc.) then it's a godsend to have and I think some headphones/buds allow you to switch it on or off. But really, people are paying far too much for this kind of gear.