Either is acceptable: https://www.merriam-webster.com/grammar/em-dash-en-dash-how-to-use https://www.merriam-webster.com/grammar/em-dash-en-dash-how-... Also,

Either is acceptable: https://www.merriam-webster.com/grammar/em-dash-en-dash-how-to-use https://www.merriam-webster.com/grammar/em-dash-en-dash-how-... Also, a comma is a pause — and what a wonderful thing — whilst an emdash is a tangent.