Right now, I have two questions:
1. Does this
contain something more than the information already available on the website for free?
2. Are all the languages represented on the Ethnologue maps or are some of them omitted?
AFAIK all of the information in the digest is available on the website. It is just organized differently, for example, it has a list that lists the languages in order of number of speakers, another list that groups the languages by province, and so on, whereas on the website the languages are only grouped alphabetically. You can use the information from the website to organize a list like that yourself, but in the digest they've organized it that way for you.
Caveat: the amount of information that is available on that website "for free" depends on your location. Where I am, for example, it's not possible to view any maps or country digests for free and only possible to view a limited number (about 5 I think) other pages for free per month. To view more than that you have to have a paid monthly subscription. In some countries everything is available for free. So whether or not purchasing a document is worthwhile depends on what you already have access to for free in your region.
So it's hard to answer your question, since I don't know what YOU can view for free. But to the best of my knowledge the digest contains information that is available on the most "free" areas of the website, plus the maps, which you can probably view for free already but I can't.
As for the languages listed on the maps, it's my understanding that their intent is to include every language. Whether or not they've succeeded in doing so for Indonesia, I'm not certain. I know that some maps in general do have a few errors or languages omitted for various reasons, but most are pretty good. (I subscribe to their feedback page and I've seen some comments there about corrections for language locations in Indonesia, for example, a correction was made regarding the location of Keninjal on their map a while back, and so on.) They are constantly making corrections, which is both good and bad: good in that they are open to feedback and take it seriously, bad in that any pdf-format document may not reflect those changes and therefore not as up-to-date. I'm confident they'd sell you the most current one, but there would probably be future changes made after that.