But it’s not very clear who needs them
The Nvidia H100 accelerator is not aimed at the consumer segment. Moreover, there are variants of this model with an SXM interface that cannot be installed into a regular PC at all. More precisely, it was impossible, but now it is possible, since adapters have appeared on the Chinese Internet that allow this to be done.
The SXM-to-PCIe adapter is focused on the SXM 5 interface, which is exactly used for the Nvidia H100. You can buy it from the Xianyu online store for just $16.
Concerning the upcoming Nvidia accelerators of the Blackwell generation, there is no information about the type of interface, so it is unclear whether they can be used as well. However, until now Nvidia has changed SXM options with each new generation of its accelerators.
Who needs such an adapter is not very clear. The average consumer does not need the accelerator itself, but for those who are really interested in the H100, Nvidia has been releasing, for example, versions with PCIe for a long time.