A list of words isn’t a dictionary. What a dictionary adds over a list of words is all the relationships between the words needed to interpret them and use them, and all of that is in the weights.
Amusingly for https://en.wikipedia.org/wiki/Special:Diff/325776830 , the last place to use /usr/dict (Debian, which changed it in 1998; Berkeley having changed it in Net/2 in 1991) stopped doing so years before Wikipedia was invented.
Sure, but the fact that people are doing something isn't evidence that it isn't a mistake. Also they may be stuck due to concerns about backwards compatibility. There may be games and utilities they are shipping, that come from upstreams, that rely on these files.