Dealt with a manufacturing company that has ISO certification. TONS OF PAPER WORK and covers many many things including work flow. High costs.

It is useful if you have business with INTERNATIONAL companies. That means they can skip a lot of certification requirements needed to do business with them. As close as Singapore & Thailand.

The bad is product and services costs will be much higher. So you will have a hard time getting chinaman business due to high costs, unless they are reselling/ repacking your business as part of theirs. so in their final presentation, they might say,

"products/ services are developed/ produced/ deployed in conjunction with ISO certified company."

I also encountered this 15 years ago.