The problem zkSafe solves

Until today, you could control an account only using private keys. Now with zkSafe you can use your wallet also with your web2 accounts like your personal email or your twitter account. This is possible thanks to Gnosis Safe Module framework and Sismo zkConnect single sign-on. But not only, you can implement social recovery with your friends and family or realise access control schemas to your wallet based on Sismo claims and levels. More over, you can make your self-custody more resilient and flexible managing all those rules off-chain with the privacy preserving guarantees of zk proofs.

Challenges I ran into

Worked very close with the Sismo team, which was very supportive in several stages. Thanks Leo, Gabin et all for all the support. All the bugs/issues I've found out were part of the game and was handled very well by the team.