You must own Lossless Scaling for this to work.
My experience with using it generally good. It has way less added latency than game’s built in frame gen through FSR/etc. which makes it the only viable frame gen option for most games on deck.
If you can get a fairly consistent 30fps in a game, you can use this to go up to 60fps and have it work pretty well. If you’re running below 30 fps or if the game’s fps is very unstable, this may add too much input latency or not feel smooth.
I’ve been running it with Genshin Impact for a month now. 90fps at very pretty graphical settings, and still barely warm to the touch. Given how I have to play with 200ms+ latency anyway it’s just free real-estate!
Yet to get it working with Control with HDR though.