Another important issue is that not every element used as a logo or brand is suitable for registration as a trademark. This is true even if it is actually used in trade as a brand.
The competent intellectual property office may refuse to register the mark without "distinctiveness". Also, another entrepreneur may interrupt our registration.

A brand (logo) allows customers to distinguish goods and services of the same type but from different sources (from different entrepreneurs). Thanks to this, the customer begins to connect (associate) his experiences using the product or service with a given brand and exchange this information with other potential customers. The representation of a brand in the customer's mind allows the customer to quickly decide whether he wants to repeat his choice of a given product or service in the future because he is satisfied with it. Under the law of European countries, the logo and the trademark can be the same asset. However, registration is a must.

Designing your brand - legal issues clarified for entrepreneurs