Steaks aren't typically cooked under vacuum pressure. Dave Arnold uses Ziplocs for steak.
Not when he's going to re-therm. Also, from the post I linked above:
A rib-eye was salted, seared, placed in a vacuum bag,
and cooked at 55 C for 1.5 hours, chilled, stored for
two days, rethermed at 52C for one hour, seared, and
served
This isn't what we want. We want the salt to effect the outside of the steak the most, the portion that will be exposed to high heat when searing, because that's where the most water loss will come from.
With a slow cook in a combi oven, the characteristics would be still different.