Good idea, I am doing that too for now. But make sure to only apply that to indices. A single stock might go to the moon because of a buyout / breakthrough etc., but the big indices are not going to jump by these extreme amounts. It is like buying a "micro put", but the time decay works for you instead of against you. Because that discount certificate is - under the hood - a covered call options strategy.
of course indexes, single stocks is way too stressy ;)
I think discount certificates are the "opposite" of those options?
The bank takes a number and sells options above and under that, and the "center" part is the discount certificate? (minus the banks profit)
Anyway.... with options you pay and may lose all that, so I don't like them ;)
Normally it should also mean you make less than bying the index on the long run, because of the part the bank keeps. On the other hand studies seem to show that discount zertifikates actually outperform, maybe because the option buyers lose more and that is the part you get to keep?
But I think the point is the flexibility. As long as you get more for the certificate than the long time average, you get out ahead as long as you switch from certificate to the index after a drop.
Or in other words: What you safe each month, put in discounts with a cap a bit under or at the current price, and when those certificates make a loss, buy the index itself.