Mixing semantic web techs with ML is hot in the domain right now.
Because ML solves problems symbolic approaches cannot solve (dealing with huge amounts of raw, poorly structured data) and symbolic approaches solve problems ML cannot (dealing with logical reasoning and inferences, like in the query "give me all cities of more than 1 million inhabitants that are less than 300km away from Paris, sorted from southernmost to northernmost").
Because ML solves problems symbolic approaches cannot solve (dealing with huge amounts of raw, poorly structured data) and symbolic approaches solve problems ML cannot (dealing with logical reasoning and inferences, like in the query "give me all cities of more than 1 million inhabitants that are less than 300km away from Paris, sorted from southernmost to northernmost").