A trademark search is necessary for due diligence purposes.
A trademark search shows possible plaintiffs. Does your business’ trademark cause a likelihood of confusion with other trademarks that are already registered or in use? It is impossible to judge without a trademark search.
Potential plaintiffs are those whose marks are either registered before your mark or in use before your mark. Many businesses find themselves as defendants in either trademark oppositions in the Trademark Trial and Appeal Board or in trademark infringement lawsuits in federal district court because of the lack of a trademark search. Finding these potential plaintiffs helps to judge the risk of being a defendant in a trademark dispute.
Alternatively, if a business has already registered a trademark while your mark is in use, then you will need to dispute that registration. Is it worth that dispute or is it more economical to find a new trademark?
Analysis of the Trademark
A trademark search reveals how strong your trademark choice is. For example, if there are 50 other similar trademarks in economically related goods/services, then the trademark you chose is particularly weak, especially if the trademark itself is related to the goods/services the mark is to represent.
If a trademark search shows that a trademark is in a crowded field, then it may be better to find a new mark. Fanciful trademarks are stronger and will probably live in a less-crowded field, making them easier to police and enforce.
Definition of the Goods/Services
Businesses have competitors. Those competitors sell the games goods or services. One of the better methods of finding the best goods/services description for your trademark application is to review all the goods/services descriptions of competitors in order to discover the broadness or narrowness of your trademark application.
All of these reasons are why a trademark search is important before use or registration of a trademark.