When printing out the odt sale report for example, and sending an email.
In the mail received, the preview of the odt file attachment, the layout of the report is not good and add a first blank page, despite that if you open it normally with Word or OpenOffice it looks all fine.
For portability it is probably better to send PDF.
The OpenDocument format may contain a “Thumbnails” folder but relatorio does not generate any and even remove them. So I guess it is the mail client that generate it wrongly.
But I can see that OpenDocument has a setting name SaveThumbnail which could be set to true. I do not know the implication of such settings if there are no Thumbnail in the file (I hope it is just ignored).