So far the following points have stopped me:

• The interest payment is not only for amounts on Savings,
• The interest payment could lead to more conversions and thus further increase the virtual supply of STEEM.

Yeah, this is why I mentioned the need to monitor and adjust. There are risks, but TBH, it's hard for me to imagine that it could make things much worse - as far as incentives go. To me it seems like the potential upside outweighs the potential downside by a long shot - under current conditions. I think the main time to reevaluate will be if/when the STEEM price crosses, convincingly, above the haircut threshold.

(It would even be possible to set up an SPS burn proposal to offset the amount of the new interest, but that's a topic for a different day. I'm not advocating for that, but it might be something to think about.)

it is not clear whether the exchange will forward the interest to customers

I think this is one of the main reasons that interest was stopped in the first place. People didn't like seeing the interest going to the exchanges. But in the wake of the Upbit delisting, I'm starting to think that a little bit of incentive for the exchanges is a good thing. And it can be hoped that their customers would eventually pressure them into sharing the windfall.