An executable is a file packaged with the Flash SWF and
displayed in the included Flash Player window. It is not reliant on
a browser window, nor on the browser Flash-plug-in being available.
On the other hand it is not "streamable" so is nearly worthless
when accessed from a slower connection (dialup).
The SWF/HTM output is designed to be accessed as (viewed on)
web content. While it will be slower to "stream" on a dialup, it
will, as opposed to an EXE which must be downloaded to the local
machine in its entirety, then run on the local machine.
I know nothing about Blackboard - it seems similar to Adobe
Connect but maybe not - you'll have to ask someone else about that.
In short, the only time an EXE is useful is when it is run
from a CD by design, especially in circumstances where no
connection to the Internet is available.
Since you need none of Captivate's features for training and
apparently have no intention of actually building eLearning content
(unless you call a Power Point presentatin "eLearning"), you are
spending a lot of money just to have a PPT-to-SWF converter, and I
have to wonder why? There are other products out there that are
specifically designed to make Power Point conversions to other
formats ... just thinking out loud.
.