The risk is if it goes over 30%: at that point the haircut mechanism cuts in to protect Hive's price from a death spiral, so HBD gets devalued whenever the debt ratio is over 30%.
But in practice, you can expect that if the debt ratio starts to approach 30%, there will be more conversions of HBD to Hive before the haircut point is reached by experienced traders, reducing the debt ratio again and avoiding the haircut effect.
I got it. Thank you for the clear explanation.
As for the conversion of HBD to HIVE, I find this helpful: