These are all valid points but many organisations are not at the level of maturity where the inputs to the engineering team are of the high quality you're describing.
Additionally there's an element of negotiation or dialogue around requirements which can often lead to cheaper/quicker to market/better solutions with input from engineering.
Additionally there's an element of negotiation or dialogue around requirements which can often lead to cheaper/quicker to market/better solutions with input from engineering.
Both of these are much easier to do in person.