Altitude training pre-trip. Useful or not?

I am doing the Gokyo circuit in March and am wondering as to how useful something like this pre-trip would be? https://altitudecentre.com/metrafit-pod/

I have hiked at altitude before (4600m), and I was totally fine. This will be slightly higher of course, plus past performance does not mean I will necessarily be fine again. I am only asking as this is not stupidly expensive so if a few sessions could genuinely help with the aclimatisation process it could remove some worry and lead to a more enjoyable trip.

I wonder how close to traveling you would have to do it though? I'd worry that any benefits would wear off by the time you got on the ground?