Many low-quality routes are of low quality because they are basically "grey routes" that take advantage of "security gaps" at a global level in telecommunications networks, to obtain the cheapest SMS. These "grey" routes are illegal and when operators detect them, they close them and the provider must find a new one.
It is for this reason that these routes typically have low delivery percentages, in addition to a careless handling of information since they jump between many nodes and pass through many providers that could be recording this information to later misuse it. It is one of those cases in which "cheap, comes out expensive": low speed, no delivery guarantee, no response capacity or limited in their form of integration.
