They do something (Banning gil farmers and RMT spammers), but that "something" is ultimately pointless when they're a totally automated process and replaced almost immediately after they're removed (The banwaves seem to occur on Saturday, but by the end of the same day, there's already a mess of new bots flying through the ARR zones...). The number of presumably meaningful bans for botting is a drop in the bucket when I've counted a few dozen different individuals on my server alone who do it occasionally or constantly; most of which have been doing it at least since SB released (Others having been active since back in HW). They're not doing a good enough job if players are so utterly fearless of getting banned that the number of bots just continues to swell as time goes on.
I feel like the issue stems almost entirely from the fact that cheaters are largely a non-issue on the JP servers, which may be giving them a skewed impression of just how bad it is elsewhere, and just how big of a team they need to be handling it properly. The STF (AKA the guys who are supposed to be managing the cheaters) are also apparently an entirely JP-based force and much smaller the GM team which means that on top of having to deal with a ridiculous amount of work, they're also likely needing to have much of the reports sent to them translated, which makes it likely that key details could be getting lost/misunderstood in the process.
Their whole system seems to be at fault, so I'm not sure how much it is to blame on actual incompetence or lack of caring.
This is precisely why having an entirely separate, foreign, and much smaller team dealing with the cheaters is a horrible idea.
The GMs are likely more then capable of identifying bots, but for whatever reason SE decided that they shouldn't be allowed to ban them and instead can only relay reports to a foreign team, which we already know has caused issues in the past (It's largely why the Ungermax glitch took over a month to be fixed after someone first reported it).
They really should just give the GMs full power over enforcing ban-worthy offenses in general.