I set up an offshore team of four in India some years back. Two of the developers ended up being lackluster and let go, but two of them continued on as they were fairly decent. Even so the cultural difference was significant and it was difficult to manage them. I don't think it was their fault, they just had a very different views on what they considered was a completed task, how they went about asking for further requirements, etc. Whilst it was worth having them, there was a surprising and hidden overhead in cost for the cultural impact, as well as timezone issues.

Later in my career I worked with a team from Hong Kong as well, the cultural gap was less significant and they were able to work well with the management style given. We still had timezone issues (moreso since I'm from the UK which is further from HK than from India), but because they interpreted tickets in the same way and had similar views on what the definition of done was things were far more harmonious.

Communication is a huge factor in remote teams, and whilst there are lots of tools to aid it, communication styles across cultures can be very different which can cause a lot of friction.