Sure! First up, we don't do repairs every time one host goes down. Standard practice on the network is to wait to do a repair until a full 25% of the redundancy is missing (in 64-of-96, that would be 8 hosts offline). Then you repair all 8 at once, significantly reducing the total amount of repair traffic.
But secondly, offline doesn't usually mean dead and gone, with unstable datacenters like this they are usually back online before the user has lost a full 25% of their redundancy.
Row level and rack level outages are handled by data randomization. The entire Sia system heavily depends on probabilistic techniques, both on the renting and hosting side. Row level failures will take out some of your data, but nobody should be disproportionately impacted by a cluster failure.
On Sia, each piece is at a different site. So 64-of-96 implies that each chunk of data (96 pieces to a chunk) is located in 96 different places. This doesn't help with the geo-bandwidth, but as discussed above there are other techniques to handle that.
Surprisingly, bandwidth pricing on the Sia network is even cheaper than storage pricing relative to centralized competition. That's a lot harder to model at scale though, so we aren't as confident the Sia bandwidth pricing will hold up at $1 / TB in the long term.
And technically, most of this stuff is customizable per-customer. If your particular use case has a different optimal parameterization, it's fairly easy to tune your client to suit your particular needs.