The trick with any one-stick regardless of attachment method is to avoid burning energy when hanging from your tether and placing the stick. I started one-sticking with a 20" Hawk Helium stick and stock strap and can say it definitely works as long as you find a way to lean into the tree trunk and trust your rope so you're not fighting gravity to place the stick. I later switched to an EWO one-stick with a Monarch platform. Yes, a cam cleat speeds up the time it takes to place the stick... BUT where you'll really find movements become less taxing and more efficient, regardless of attachment method, is when you can pinch the stick between your tether and the tree trunk so both hands become free to work.
Unfortunately, there's not a great way to do this with a stock Hawk Helium stick, or any one stick for that matter, which doesn't have a platform, because the stick stands too shallow against the tree trunk. A stick with a platform projects far enough to create a nice angle to wedge the stick against the tree between the tether choke on the trunk above, and you below weighting the rope in your saddle.
Last season when my cam cleat broke (my fault, overtightened it using tools) I reinstalled a versa button on my one stick, used a rope and prusik attachment method, and it still worked almost as easily as a cam cleat, simply because I still wasn't fighting gravity by letting the rope pinch the platform against the tree.
Greg Staggs shows this well at about 4:30-5:00 in this video: