It's about value. If you can get a Dansby replacement (Abrams) (saves you roughly $10M after 2022) and a Ozuna replacement (Hassell) (saves you roughly $13M at some point) then paying Hosmer $13M per year in 2023 is certainly preferable than paying Freeman $25M in 2023. You've theoretically saved yourself 10+13+12=$35M as opposed to hoping that a mid thirties Freeman will be worth $25M per year.
I admire Freeman. In a vacuum, I would say the Braves should sign him and keep him around. Buy him a rocking chair when retires. Just be prepared to spend the money to plaster over the cracks caused by his failing productivity as he ages. I have no interest in seeing the "grand old man" simply for that sake only. My interest is in winning baseball with a desire for a chance at a WS or two.
And yes, Hosmer, isn't a desired option for 1B. Freeman is light years better and likely will be in 3 years still. But will the difference between the two be enough to outweigh the talent and financial flexibility gained?
If you assume that, in the scenario above, Abrams and Hassell never develop or develop marginally to only become barely serviceable ML players, then you don't do the deal 10/10. But, that's why you pay your talent evaluators. I'm working from a "for instance" basis. I don't have the scouting reports that Atlanta theoretically has on Abrams and Hassell. I'm just paper scouting, which is all I can do, and firmly admit that it may not be exactly that trade that needs to happen.
We could likely do a lot more with the money saved by simply not re-signing Freddie, than to make that trade and be stuck with a terrible contract for the next 4 years.
If we're trading Freddie, you can likely expect at least 1 very good prospect in return that would be roughly as likely as Abrams or Hassell to work out. Might as well take the trade without an albatross contract coming back.