The KOMA-Script article class
scrartcl is like the standard class
article designed for (more or less short) articles. The KOMA-Script book class
scrbook is like the standard class
book designed for scientific books from about some dozen up to several thousand pages. The KOMA-Script report class
scrreprt is like the standard
report class somewhere between the article and the book class but more near to the book class. They differ from the book classes mostly in the defaults. And you can always use the book class with change of some defaults instead of the report class. So some persons say it is not really needed.
Submission of articles often should be single-sided printed. So this is the default of
article. But you can change it using option
Reports are a kind of paper often found in folders or discussed on round (or squared) tables. So they are also often printed as single-side documents. And so single-side layout/printing is the default of most report classes like
Books are almost always double-sided. So this is the default of
book. But you can change it using option
twoside=false (KOMA-Script only) or
Usually articles do not use a complete page for the document title, but put the title on the top of the first page often followed by a short abstract as an eye catcher and sometimes followed by a table of contents. Not using a title page but a so called in-page title for titles made by
\maketitle is also the default of
article). But you can change this default by option
Books usually have several title pages (don't mix this with the cover!) as part of the book block. Usually books have a half-title. This is the first page of the block. It often does show only the main title of the book. The verso page of the half-title is either a blank page or the frontispiece. The next page is the main title page with title, author and several more elements. The verso page of the main title is often a kind of imprint with legal notes, edition, printer etc. The KOMA-Script
scrbook does provide all these pages (and also a dedication page) by default. However you also can switch back to a in-page title using option
The abstract of a book is generally a chapter (with or) without a number.
Providing or not providing a special
abstract environment indeed has consequences for the available options. For example the KOMA-Script option
abstract wouldn't make sense in
scrbook. So only
scrreprt provide this option.
Parts, Chapter, Section …
Sometimes in books the titles pages, the preface, the table of contents and some other tables/lists are flagged by roman page numbers and not numbered chapters headings. Book classes therefore provide commands
\backmatter) to separate these parts. Even though the KOMA-Script author is not a fan of roman page numbers,
scrbook also provides these commands.
Article do not have such a separation into front, main and back. So article classes usually do not provide commands for it. (And so are reports).
Usually articles do not have several parts. If they have parts a part heading is a heading like others too. It does not begin a new page nor have a page on its own. This is like
On the other side the parts of books are more or less independent and therefore a major break inside a book. Often parts have a kind of main title page with blank verso. This is like
book) work. But in KOMA-Script you can change this.
Usually articles do not have real chapters with a really eye-catching heading starting always on a new page. Therefore
article do not provide
Books do have real chapters. And to make them eye catchers, chapters always start on a new page, mostly on a new right/odd page. The heading is not aligned to the top of the page but starts after some white gap. The start page mostly do not have a head resp. a running head. This is
book). But in KOMA-Script it is only a default, that can be changed.
Sections of several levels (
\subsubsection) and in-line headings (
\subparagraph) are also supported by all three KOMA-Script (or standard) classes.
The difference in providing or not providing chapters has indeed consequences for the available options. For example option
open=right (KOMA-Script only) or
openright does not make sense for article classes.
There are several more distinctions in the defaults of
scrbook. But most of them can be easily changed by options or commands.
Don't ask, what article classes have that book classes do not. Ask: What kind of document do I write? Is it more an article or more a book. The main characteristic is: Should my document have real chapters that start on a new page? If so → use
scrreprt). If not → use
Private note: I often use
scrartcl for memos or notes. For software design papers I've formerly used
scrreprt, now replaced by
scrbook with option