If a site has a 1% house edge, then investing at "0.5x Kelly" should mean that you are risking 0.5% of your bankroll at the most on each roll.

As I understand it, at DaDice, investing at 0.5x Kelly doesn't limit your exposure at all. If you are the only person invested in the bankroll and you invest 1 BTC at 0.5% Kelly, you are risking over 100% of your 1 BTC, because the site offers a payout of 20 BTC no matter how much is in the bankroll. At DaDice your "Kelly" factor doesn't limit your maximum risk. All it does is change your proportion of the total risk relative to other investors.

In other words, if all the investors were at 0.5x Kelly, it would be exactly the same as if all the investors were at 10x Kelly. The maximum bet would be the same, and amounts risked would also be the same.

I'm not able to see the investment interface. It was hidden a while ago.

Could it be un-hidden on my account so I can see how it looks? My name at DaDice is "doog" (it seems someone already registered "dooglus").