Because I have Desktop Pro 2018 and email no longer works. I wanted to get the last version before Quickbooks went totally subscription. Doesn't seem that is going to happen. So, it's an extra step to send an invoice but I'll have to live with that I guess. 

Beware of scams on Amazon. They just got me advertising 2021 Desktop Pro 3 user. Yeah they sent an electronic version oddly enough linked to the Quickbooks download site. The license number and product code worked to activate the product however it turns out it does not show up in my account purchases and it is for ONE user only. Hoping I can recover the cost with one of the various "protections" offered by Paypal and/or Amazon. 

Hope dies hard....