I dont know Im not a huge fan of this comp rn but it makes sense.
Even though chamber is good at taking fight angles on A and C but he is useless if Omen just smoke a one way on the choke point.
On defense his util is not nearly as good as other senti like Killjoy and cypher and he can easily be smoked off.
Right now most teams is using chamber as a opper that means if he loses the op it will be a huge hit to their economy easily which is really not a good thing to do