Exterminators have many tools in their tool box to battle bed bugs and the bug sniffing dog is one of them. There are times and places where a bug sniffing dog can be very useful. But there are also times and places where other tools are cheaper or more effective.
Perhaps the ideal use for the bug sniffing dog is in public areas where there are no specific hot spots that would harbour bed bugs. An exterminator with a visual only approach in these cases is at a woeful disadvantage compared to the dog. Even glue board monitoring traps will be ineffective in these settings because the chances of randomly catching a bed bug is very remote.
But one must also recognize the limitations of the dog in these public settings. Suppose the dog was to inspect a library. The dog must put his nose relatively close to each area and given that there are literally millions of places to inspect the dog will be unable to give a 100% OK. Also most of the books in this library are on tall shelves which are beyond the reach of the dog. As such the exterminator must acknowledge there are limitations to this particular tool.
In residential settings the usefulness of the dog is not as clear cut. An exterminator can walk into a room and can guess pretty accurately where the bugs will be and where they will not be. As such the exterminator can carefully examine the high risk areas. If there is nothing in the high risk areas the likelihood of finding bugs in low risk areas is very small. As long as the infestation is 6 weeks or older the bugs are relatively easy to find.
When the infestation is very small (a few weeks) the exterminator would have a hard time finding a single bug with a few first instars. The bug sniffing dog would be helpful in this setting. But a cheaper method is available with isolating sleeping surfaces with glue boards or climb up interceptors. Leave these tools in place for a few weeks and they are just as effective as the dog. Actually one could argue these tools are more effective because a positive finding with the dog still requires the exterminator to find the bug. Finding a single bug is sometimes difficult even if the dog pin points a location. If nothing is found the dog may not have given a reliable assessment. But an actual bug caught in the traps is proof positive.
Also waiting for a few weeks with the traps makes the bugs more obvious with a manual inspection if the bugs are already on the bed. The dog handler might argue that allowing the one bug to multiply for a few weeks is not good practice. The non dog handler would argue that the difference between 2 weeks and 6 weeks is not that great and the interceptors /traps would prevent the bugs from leaving the bed which reduces harm. I would fall into the latter category as a 6 week old infestation limited to the bed is easy to address. And the cost would be considerably cheaper without the dog.
As with any tool there is a place and a time for effective use. The same goes for bug sniffing dogs.