I know from personal experience that you were "coached" to do so. You could choose another bank, it is "your company", however it was clear that it was frowned

I know from personal experience that you were "coached" to do so. You could choose another bank, it is "your company", however it was clear that it was frowned upon and could quickly put you outside the circle of trust. Also, for the most part, when you get your real funding, a CFO is "brought in", as most founders teams do not include a CFO from the start. Similar for various services, technical and otherwise, if there was a portfolio company that offered these services. This is from almost two decades ago, things may be different now.