Do ecommerce digital product website should have login function.

Hi,
I am creating powerpoint templates from past 3 year. So, i thought why not open a digital product selling woocommerce website. I got it done from someone. Now iahve a confusion in the work flow. Whether user should login to website before purchasing anything. And if you wants file that he purchased should it be available to download after login. Some people say login option is not required abd there should not be option to download as one user can share pasword with everyone.

Please suggest. I need to urgently respond to seller.

Thank you.