How to invest safely in cryptocurrency? It's simple - stick to Bitcoin and Ethereum. 90% of all coins are either outright scam or are useless or will never gain any significant traction.

As many said in this post, you can easily buy crypto with your credit card on most exchanges. For example Coinbase and Binance (no identity verification for small amounts) offers such possibility. Nowadays crypto wallets like Atomic are offering such possibilities too. You can also check KyberSwap as they now allows easy purchase of Ether using credit cards (https://twitter.com/KyberSwap/status/1172447392685154305).

You are wrong. Ethereum developers are working hard and there is so much happening around the network - see how DeFi has grown in past few months (https://twitter.com/alethioethstats/status/1162426236636938240), EY (https://www.coindesk.com/ey-open-sources-nightfall-code-for-private-transactions-on-ethereum), Microsoft (https://www.coindesk.com/microsoft-releases-ethereum-app-development-kit-for-azure-cloud), Santander (https://cointelegraph.com/news/santander-issues-20-million-end-to-end-blockchain-bond-on-ethereum) - more and more companies are jumping into this train.

Of course there is scalability problem - right now Ethereum network almost reached it's capacity, but dev team is working on that and transition to Ethereum 2.0 will start next year which will hopefuly solve this problem.