This is a quick note on Exploring Options for Storing Custom Data in Ecto · The Phoenix Files
As far as I know, in terms of backwards compatibility of term_to_binary/1, the guarantee that Erlang gives is the following (https://www.erlang.org/doc/system_principles/misc.html#compatibility):
Erlang Distribution
Erlang nodes can communicate across at least two preceding and two subsequent releases.
I imagine the format is not really going to change much at this point, but still you run the risk of having to re-encode the data in your tables in the future. Quite an important con to that strategy, especially if there happen to be minor changes over versions and you implicitly end up changing formats without even being aware of it at the time.