It makes sense in some special kind of situations when it comes to big companies.
At my current employer I also have witnessed some situations like this, where we are suppliers and have done this also to sell third-party stuff (sometimes rebranded, and sometimes only repackaged/bundled) with our own stuff. We basically sell our own software (programmed in-house) and then have some safety testers (device testing) that we resell from a big brand, but with modified firmware. And then we have some small stuff like test leads, adapters like C13/C14->C19/C20 or to the butterfly/mickeymouse connector for notebook psu- this stuff is bought from a reputable company, and we offer it to the buyer with a "moderate" increase in price (usually 100%) to cover our handling costs.
Some companies are quite happy that they can also source those small parts with/through us, because it is in the long run easier and cheaper for them:
- in big companies you have every supplier registered with central purchasing (and they do not like to go through the whole process for a single small order)
- they only have to do one order instead of two, saving the amount of ordering, check incoming goods, checking the invoice and paying it (in big companies easily one or more hour in total throughout several departments)
- a single source to complain to when something does not work
- a single source to obtain paperwork like CE documents from, because we as the supplier are responsible to make sure we can provide them on demand
- when it comes to specialized stuff like adapters (for appliance testing purposes (in germany DGUV V3 or VDE 0701-0702), looking for the original supplier of some small stuff where a company only will need two or three pieces of maybe 20 € each it does not matter if this stuff costs 20 or 35 €€€, when the amount of work to look for the original manufacturer AND then getting procurement to list a new supplier etc. will take several hours of labor
I agree with the quality of Knipex and Wiha, they make very good tools- with pliers i like the Knipex a bit better in direct comparison. (Have them both at home and at work)