The homes in this portfolio are not commercials. Blackstone purchased portfolios of SFRs and multis post-crisis at depreciated prices, and have been servicing the pool since. PE funds do not typically IPO on alternative assets (although RE doesn't count as one) bc they can source private and cheap capital. IPO-ing this REIT effectively means they want to grow and lets be honest, their only other source of capital would be to issue debt.
In my opinion, this does not signal RE values will decrease - although upward trending interest rates may have that impact. Blackstone can utilize the capital for other investments and purchase more homes, and they also make a killing on servicing fees of this pool. They see this more of a long-term business i think, otherwise, they would exit the opportunity, and its really not that hard to do so - typical valuations of on-lease rental portfolios can sell at 1.2-1.5x book value so they can make more than par.