Allow SKU for Bookable Products
Consider moving SKU out from the Inventory tab (which gets hidden for Bookable Products) to general so that a SKU can be set. This will then allow people to easier target the product when using the [product sku=""] shortcode.
The inventory tab shouldn't be just hidden when it is a bookable product.
There is a WordPress plugin: https://wordpress.org/plugins/sku-for-woocommerce-bookings/
Perhaps this helps: http://rynaldo.com/how-to-add-a-sku-field-to-your-woocommerce-booking-product/
Having a SKU for bookable products would also mean that when you have a coupon and import it you can apply it to a specific product.
Shaun C Wilson commented
Having a SKU for person types would help us integrate bookable products into point of sale systems