Here is the problem with full line emails and is the reason for chopping the emails in the begining...

Not all email clients are equal. They can restrict the line length to different lengths. When reading online you must give plenty of white space to make it easy to read.

You may keep each paragraph to 4 lines but at full length an email client could cause that paragraph to be 8 or 10 lines and make it hard to read. Thus your emails are then closed without being read.

Formating emails to 55 or 65 characters are very easy to read in all email clients and you can now control how many lines you have per paragraph.

The font may be small when you send the email but may appear large in other peoples email clients making the lines per paragraph even worst.

The reason you should format your email is to get them read because you do not know how they will appear to the reader. Formating gives you more control.

Best regards,
Steve Yakim