I also knew that there are browsers with built-in wallets. Did you know that it's not just Opera? The most popular among digital asset owners are three web browsers: Brave, Opera Crypto Browser, and CryptoTab. Brave is #1 among crypto browsers, it is focused on anonymity and security. Opera Crypto positions itself as a web browser for Web3, and CryptoTab's main feature is built-in PoW mining.

1) Brave Wallet. To make the web browser interesting for crypto users, the developers have integrated a non-custodial Brave Wallet into it. The wallet supports a large number of blockchains and resembles an improved version of MetaMask. It can be used both as a widget that has a compact size and is located on top of the tabs, and deployed as a standalone tab for full balance detail and access to all functions. Supporting more than a dozen different blockchains (including Ethereum, Binance Smart Chain, Solana, Polygon), Brave Wallet allows you to store all the assets of these networks. From the wallet, you can transfer tokens, buy new coins for fiat using Visa/Mastercard payment cards or through Ramp Network or Wyre payment services. In addition, it is possible to store NFTs and follow market trends by viewing graphs of changes in asset value. Brave Wallet supports multi-accounts, an unlimited number of wallets of any asset, as well as import from hardware wallets.

2) Opera Wallet allows you to store crypto assets and NFTs, as well as connect to dApps without installing additional plugins. The crypto wallet supports ETH, ERC-20, and ERC-721 tokens, as well as various blockchains, including Bitcoin, EVM-compliant networks, and Layer2 solutions. Opera Wallet allows you to buy cryptocurrencies for fiat and perform swap transactions.

3) CryptoTab. This is a regular free web browser with the only difference being that it offers rewards for PoW mining in pools and a referral program with motivation for attracting new users. Rewards are paid in BTC to a built-in wallet and can be withdrawn after reaching a certain limit. The amount of reward depends on the hashrate, CPU power, and the number of invited referrals.

Recently, there have been a lot of reviews about the meager mining fees in CryptoTab and the inability to withdraw BTC from the wallet. It's also worth remembering that PoW mining on the CPU threatens your processor. Therefore, it is up to everyone to decide whether to accept such risks and try it or refrain. In any case, CryptoTab positions itself as a web browser for crypto miners.

However, I don't think it's a good idea to store cryptocurrencies in browser wallets. It seems to me that it is better to use high-quality and already proven wallets.