If it’s a complicated matter that could use a lot of back and forth, sometimes it’s expedient to call or share a screen rather than send a dozen emails back and forth.
But that doesn’t at all seem to be the case here. Even the email seems very unnecessary. Maybe they were trying to upsell you or something? I really don’t like it when you can only order something by calling rather than on the website, but maybe they think they can charge more or sell more if you talk to a sales person?