1) personal accounts have small limits
2) you can't get advantages of international tax planning without using companies, all your income is your personal income and will be taxable in your country of residence
1). Legal Tax avoidance.
2). Added confidentiality.
3). Can do business which otherwise is not allowed in your country e.g Crypto etc.
4). In case your country goes Bankrupt like Greece or is in financial crisis you money will be safe in another country.