Because a lot of people don't understand how the products work or what they need. Trying to understand a complex product, with multiple options that come with advantages and disadvantages, and having adding on top that it's a very consequential decision is much easier if any misunderstanding can be corrected and explained real-time. The alternative is to do it async with some lead time for every back and forth.

Your pizza order needs no clarifications and if you get it wrong, it's just a pizza. If you misunderstand your mortgage you're looking at far more costly consequences.

For some people, the mortgage application process can be complicated.

Maybe I'm in graduate school and my salary is called a 'stipend' and I don't get any payslips, plus I have a part-time job in sales where my base salary is very low and about 75% of my income is commission, and also my girlfriend will be helping with the mortgage, but not the deposit, and she's a Ukrainian refugee and self-employed content creator.

An expert who's seen it all before would know how to navigate my situation properly.

I agree! I am a big fan of synchronous comms

I think getting a mortgage might be a tad more of an impactful decision than ordering takeout... I'm not a boomer but I still would like to speak to someone in person before I sign an O(million$) loan.

Why do you need someone to show you the calculations? All of the important numbers including principal, fees, points, interest rate, and amortization schedule fit on a short PDF. You can verify the calculations yourself on a pocket calculator if you want, it's like grade school level arithmetic.