I'm assuming when they say that this improves user experience, that it implies the use case is primarily TLS. In which case store-now-decrypt-later attacks are already considered an urgent threat with regard to post quantum crypto. With FIPS 203 being released and Chrome is already using an implementation based on the draft standard, this seems like this algo (at least for TLS) should be on its way out.
Thanks I forgot about that. So if understand it right, the idea is to provide some insurance in the case that these relatively young algorithms are broken as they get exposed to more and more cryptanalysis
No one other than NIST is recommending phasing out pre-quantum crypto. Everyone else is using a combination of pre-quantum and post-quantum because trust in the security and robustness of the post-quantum ecosystem is fairly low.
