Probably going to have to test it yourself, my guess is that it will be slower to use instances as the foliage tool appears to group instances together in chunks. Not sure it will make a big enough difference to matter though (maybe if you have a really big world?)
I read up about one in particular called Scatter 5 and then about the workflow you’re talking about. Looks like it has the ability to really create natural distribution of foliage. On a side note if its bigger landscape and you need and its low foliage like grass etc. that doesn’t need collision a landscape material that called to a grass layer is always has much better performance. In addition, I don’t know if you’re aware but UE has a procedural foliage volume experimental feature that does many of the same complex things that Scatter does. Not only that its super high performance because it essentially only uses a single foliage instance and replicates it across the entire landscape. Its another option to consider if performance is important.