That's a great question! Yes, that would be possible, but there are specific reasons why we chose the current model:
1) derivatives for BTC & digital assets are just the first step for us, with later additions of alternative assets (PE/VC fund shares, commodities, real estate, etc.) as underlyings, and then capital market assets (stocks, bonds, FX). Thus it's hardly imaginable that NASDAQ, CBOE, CME, HKEX or similar ones would be operating on non-custodial model
2) As the current trend (which is unlikely to change very soon), custodial exchanges aggregate greater liquidity via market makers, partners, and retail traders, while the second one normally doesn't to such extend. Therefore, we aim to provide customers with the best currently available liquidity to ensure you get executed trades fast and at best prices.
3) We are not "just another crypto-exchange" where developers raise public money, do DeFi, issue useless internal token or something and put all responsibility on end-users for asset safety. So with them - if you lose it for some reason - it's your problem. On the contrary, with our model - we fully understand and take full responsibility for safety of each single client. And if something happens - we will be responsible for full compensation.

Due to the above, currently we operate as custodial CEX.