Yes - the proceeds of the STEEM power down still belong to the SPI holders. The liquid will be used for off-chain investments.

We are working on specific details for a couple of members that may want to request a buyback of their SPI. A plan will be finalised but it will probably involve buying SPI tokens back at 95% of the STEEM valuation over 13 weeks, with the valuation adjusted weekly. As the value of STEEM declines (if indeed it does what many of us expect), the SPI / STEEM rate changes.

Hopefully most (if not all) stick with the long term plan and we can get most or all of the STEEM powerdown into significant off-chain assets.

Please note: these are just me sharing my personal thoughts and understanding of what's happening, not the official SPI policy. My understanding may differ from the eventual outcome and should be taken as an opinion, not fact. Not financial advice.