The main benefit is the legal protection that the trademark guarantees. If anyone tries to misuse the company’s name, logo, etc. they can be successfully taken to court where the trademark registration will be upheld.
Once a trademark is registered, other entities will be deterred from using a similar name or logo. The trademark will appear in the registrar when a search is done and other entities will not want to create a trademark that is similar to one that already exists.
In the case of infringement, the owner of trademark is eligible to receive up to three times the damages from the infringer. As the owner of the trademark, the individual or company has the right to sue anyone who infringes upon their brand and will be awarded the decision. Without the trademark registration this is not possible.