In a word, ABSOLUTELY.
If the seller chooses not to have a realtor represent him, that is fine and that is his decision. However, you do not need to let that dictate whether or not you hire an experienced, qualified real estate agent to represent you. Two completely separate issues.
Here are a few of the benefits of buyer representation for you (not for the seller, just for you):
1) Objectively inform you about the positive and negative aspects of the property and how those might affect the value (the seller is not objective), as well as show you other comparable homes. You need to comparison shop to know you are getting a fair price, and it's your realtor's job to provide you with an opinion of value of any home may be serious about buying, whereas the seller is focused on his asking price. Also, objectively help you understand the pluses and minuses of any home for your particular situation.
2) Negotiate on your behalf (there are standards and customs in terms of who pays for what - you may be aware of these, or you may not)
3) Provide resources support and advice as necessary for the process of buying a home: Mortgages, Insurance, Service Providers, Movers, Neighborhood Info, School Information, etc.
4) Generally protect your interest throughout the transaction and guide you through the whole process so that you understand what is expected and make things are handled in a manner that is fair to all parties.
See buyer resources on my website below.