I went through the same calculations and thought processes as you did, and came to the opposite conclusion. Isn't life wonderful - we are all different, and that's great!
Here's how I decided finally on the sealed mini pouches: 1) I am short. I used to be 5'2", but over the years I have shrunk and am now barely 5'. A re-sealable 9" pouch hangs halfway down my thigh, and swings back and forth against my thigh when partially full. I CAN'T STAND IT! The sealed 7" mini pouches hang comfortably to the point I don't even notice them any more. That alone was almost enough to decide in favor of the sealed pouches by itself.
2) I have rather solid-ish output. When I empty the re-sealable pouch into the toilet, it splashes me, the toilet seat, and sometimes the floor and/or rug next to the toilet, ALMOST EVERY TIME! Ugh! No, thanks.
3) Every time I used the re-sealable pouches, I could never quite get the closure clean. Every time I closed it back up there was bits of waste stuck to it that I could swear I could smell when I left the bathroom. Again, no thanks.
Instead, I remove the pouch, clean myself off with moist wipes, and snap on a new pouch. Old pouch into the disposal bag, disposal bag into the trash. Every few days, trash out to the trash can. I use the mildly scented bathroom can liners, which keeps down the odors in the bathroom.
Perfect? No, but neither is anything in this world! Cons: The disposed bags are in the trash for a few days, but a lidded trash can and the scented trash bags really keep the odor down. Also, I definitely use more than just 2 per day. You just can't argue with Medicare (well, you can, but it doesn't get you anywhere!). So I buy extra boxes on ebay as I need them. Price varies depending on when you look - I have paid anywhere from $50 to $100 per box of 60, so there is a cost issue. However, in my mind the convenience and the wearability so outweigh that, I am happy to "pay the man" as they say.
I strongly suggest that you contact Hollister or whoever makes the supplies you use, and ask for some samples of different kinds of pouches, re-sealable, closed, regular and mini, and see how they work for you. Hollister, Coloplast, all the big manufacturers are more than happy to send you all kinds of samples. That's how I finally decided on mine.
What it all boils down to in the end, is whatever actually works well for you is what works well FOR YOU, in spite of anybody else's experience. And we all have different factors we weight differently in making our decisions.