It's not only that, though. It's this:
1) You will be able to purchase and run the 5e Adventures with no work to convert.
2) You can use old monsters alongside new ones.
3) You can play exclusively 2014 characters at the same table as exclusively 2024 ones.
4) You can mix-and-match 2014 & 2024 PC options. IF you (and your DM) are willing to do the "work" to convert whatever mismatches occur. They have explicitly said two things on this subject: A) Before press, they will do a final review of the 2024 rules with an eye on compatibility. This means that they will look to see if the new version is adding anything of substance, and if it is not, or if it is too confusing for no real gain, they will revert to 2014 versions. B) They will print side-bars on how to make any necessary conversions that remain.
The only thing a table needs to decide is if they can handle 4, or if they feel that it will be too open to exploitation, at which point, your DM can simply not allow it; which is essentially the same thing that happens any time that there is errata or splatbooks anyhow. Maybe this will be a little more complicated than that, but I don't think it will be by more than a degree or two, tops.