Odessa is a fine commercial port, but the Russian Navy facilities at Sevastopol are more important to Moscow, as are its major air bases in Crimea.
Putin will have a bit of trouble rigging an election in the Oblast that controls the land approaches to Crimea with only 14% Russian population.
The Chinese would be very happy to pay Putin for control of such a fine commercial port as Odessa. Odessa could also be used to supply North American LNG to Ukraine and Europe.