If you're a singer, you need to invest in cardio to support your breathing, and to give you the stamina to sing on stage for an extended period of time, whether playing an instrument or dancing. It's a good idea to do breathwork, as well as meditation to cool down one's nerves while preparing to perform live or even in the studio. If you have problems with posture, it's a good idea to do strength training. I am not perfect in these aspects, but my dance practice has helped me as a singer, even if I have barely earned any money in dance professionally.