What is the big deal with ETL tools ? are they even needed ?

I've done a lot of custom Oracle ETL, have dabbled in Informatica (and worked beside the Infa team for a long time), and have done a bit of work in SSIS plus worked alongside the team. So I have a good sense of what's going on, I'm just not an expert on those tools.

I also see tons of job postings for Informatica and SSIS.

But are they really needed ? Why isn't custom ETL better? They're all going to be processing flat files, no ? I'm just not seeing the advantage.

I did enough with Informatica and SSIS to know that their are limitations. With Informatica, the guys just shrugged their shoulders. With SSIS, I found limitations even quicker, plus others would just write a stored procedure and then the only thing the SSIS program did was call the stored procedure.

So what is the good points for the ETL tools ?

It's a huge learning curve to be really good with these tools, and so it requires another skill set, tool base, etc., etc. Plus I've also found the ETL developers knew a lot about the tools, but less about Sql and even less about whatever business is at hand.

So what IS the big draw for these tools, and what do the old-timers here say ? The only thing I can think of is that is Windows based and so you don't have to fiddle with Unix, scripts, etc.