I've not tried it, but it sounds like an interesting solution. One concern would be the material used for the pouches; something like PP may not work for the longer term (beyond a few weeks) due to oxygen permeability issues.
This is why I've not attempted using a food vacuum sealer to store dry chems, let alone mixed solutions - I cannot guarantee that the plastics in use have good air barrier properties.
For mixed chemical stock, I used appropriately sized brown bottles. I find the 1/2 gal / 2 liter "growler" bottles perfect for mixing and storing stock film developers, and working strength Ansco 130 paper developer. I have used D-76, D-23, Beutlers, DK-50 ... stored in these glass bottles for moths - even partially filled - and there's been no noticeable degradation in developer action.
For Pyrocat, PMK, and 510 Pyro, I use 250ml - 1 liter brown glass bottles as is appropriate, again with no developer failure after months of storage in partially full bottles. I suspect (but cannot prove) that the amount of air even in a half full glass bottle contributes to far less oxidation that storing the whole business in an air-permeable plastic container.
The advantage of the glass 1/2 gal growlers is that beer comes in them thereby putting them to very good dual use ...