Originally posted by reh321 The small point-source flash was added to SLR cameras about the same time auto focus was added and mediocre f-stop variable-focus kit lenses replaced fast prime kit lenses. At the time, I thought the manufacturers were trying to make it easier for point-and-shoot users to upgrade to SLRs. Maybe they have finally reached the point of understanding that you can pack only so much into a box, so Pentax is trying to do fewer things but do them very well. After all, part of the ambiance of SLR has always been that they provide a basic system that does a very good job, and then the user can add components based on his/her needs. Personally, I have never found optical trigger to work reliably for me, so I would much much rather have an RF trigger.
What does the history have to do with it? I started out when aperture-preferred was an advanced mode. For a long time, I ignored the on-board flash in preference to use of an external flash (not to mention that the *istD had circuit board problems where the flash would drain the battery well beyond what should have been required); then I found it helpful for some specific situations in ways that other supplemental lighting further from the lens could not fulfill - including some macro and other various challenging situations. For those of us who need to craft light solutions in a portable way that includes some fill, the on-board can be a huge benefit. I've owned an advanced dSLR that did not have one - and I missed it.
As for not reliable? Really, you haven't had an RF battery fail, bad connection, let alone the myriad problems inherent in pTTL? A nice solution would be for Pentax to restore real TTL by putting a sensor in the body - that would be a step in the right direction. Instead, they abandoned the far-superior legacy TTL version in the crappy, decontented new flashes. In any event, a decent optical slave (such as the Wein HS) is virtually 100% reliable from a wide spread of angles - with a very low trigger; the only problem are situations where you have other flashes triggering. A decent optical slave gets very reliable results.