Anonymous wrote:OP, I would not do twice a week. It's too much focus that this is their only thing. Just for background ~ DD started piano in K and took piano lessons for 9 years. Came to the end of the instructional book series. She added a new instrument in 7th and was placed in Symphonic Band class (skipping several class levels) What I saw is she used that discipline in other ways, to later succeed at other things, non music related.
The bolded is key. My kid puts a lot of effort into a specialized sports position she will never use past high school. It's worth it because progressing has shown her the value of hard work, given her more grit, and made her more confident. She could literally stop tomorrow and it would all be worth it because of all that. Plus she loves it and is the one driving the effort. All we have to do is support it.