" If all the tigers and rhinos were wiped out, how would that affect us?"
As well as it not being a right to destroy the Eco System.
Those that hunt those animals and/or use them in "medicine" would look to other species, this would eventually affect us, or rather the planet.
This will/does make a negitive difference to people's lives and the income level of the affected region.
When the Tigers and Rhinos have gone, so will those paying to hunt there. So if the region relies on this it is a very short sighted plan.
If those living in that region want help to stop these practices, they should be supported.
We have to manage the planet for it to stay safely habitable.
Especially now that Globalisation and certain types of tourism has happened.