The problem Ez Wallet solves

Issues with traditional EOA wallets are vulnerable to the threat of losing your private keys or getting them stolen. Such transactions are also complex, not user-friendly, and involve heavy gas fees. You also either own the account completely privately or have to share your keys and allow full access to the wallet to allow a shared transaction. Many people have lost millions of dollars worth of crypto assets because they lost their seed phrases or had them stolen. All these have acted as barriers to mass crypto adoption. With account abstraction, the wallets are controlled by the code of smart contracts and not by external factors. This enables the "abstraction" of complexities of blockchain such as private keys from the user. Hence, even if the user forgets or loses their private keys, they can set up alternative recovery mechanisms such as biometric identification or social recovery with the help of friends and family members.
Secondly, gas fees can be removed or subsidized by the dApp owner as one person can pay for another's gas fees.
Also, a "bundler" in the account abstraction process groups together multiple user processes into one batch. This not only reduces the gas fees but also helps the user avoid the cumbersome process of clicking "sign in" and "confirm" at every step, hence improving UX drastically. This has a potential use case in blockchain-based gaming.
Further, with account abstraction, one can have a multi-signature wallet which can be controlled by two or more entities to approve transactions.

To conclude, the main problems solved are improved user experience to enable mass adoption of blockchain-based technologies, improved blockchain network security by protecting from hackers stealing your seed phrase, and reduced scope of human error by providing alternative account recovery mechanisms if you lose your private keys/

Challenges we ran into

The biggest challenge was handling the integrations of the various libraries and new web3 technologies that we used, as these are new and emerging technologies that we don't have much prior experience with. There were some issues during the deployment stage which we could fix by referring to the official documentation and running several tests.