This is quite exciting in that it removes plastic waste. I see no reason why different companies can’t make different shape ones to maintain their lock-in. I expect a knock-off market to pop-up, but that exists with plastic pods too. It’s a step in the right direction at least.
If you are blowing the seal around the shower head, it is usually because you are locking the portafilter in too tightly. It doesn’t actually need to be fully locked right over. But yeah it’s an easy fix. My issue with the sage is that it starts the slippery slope of realising what good coffee is and then you need better beans and a better this and that. The sage is an amazing piece of equipment, well made and will last years and years being reliable and consistent.