Preamble
It is in general true that structured products can be decomposed in simpler products (linear and options for example). Regardless of the decomposition of the specific product, it is typical for the bank to "buy" some rights from the customer. This is the way to grant a higher (expected) yield in structured products: there is no free lunch, if structured products have higher (than vanilla) coupons it is because you give up some "returns" in specific future scenarios. This was all abstract, let's go for an example:
Callable Bonds
Callable bonds are (often but not necessary) fixed coupon bonds that the issuer can call back before the natural maturity paying a prespecified price (typically on par).
You can see how the investor has "sold the right" to buy back the bond to the issuer. In exchange, this leads to a higher yield requested by the investor. Indeed callable bonds have to have higher coupons (everything else being equal) than non-callable bonds, otherwise who would invest in such a product? I mean, why give up a right without asking anything in return?
The point
Now I chose a specific product that involves "buying" options not to prove my point, but to show you the actual meaning of structured products: to offer a higher return (than vanilla products) to the investor, therefore making the product a bit more interesting for specific segments of customers. And to get higher returns, customers have to give up some rights: that's why these products involve issuers buying options. Nonetheless you can always structure your product so that the issuer is selling rights (like putable bonds), but it's very unusual.
Sources:
I work in a bank doing exactly what I described =)