A buyer's agent can assist property buyers and investors throughout the property selection and purchasing processes, including negotiating the best price.
Sometimes, a buyer's agent may also be a Qualified Property Investment Adviser (QPIA).
A buyer's agent carries the required real estate agent's licence for the state(s) in which they operate.
A buyer's agent can negotiate and secure you a property, but unless they are also a QPIA they do not have the extra qualifications needed to identify whether that property is right for your personal circumstances. If they are not a QPIA they may work with someone who is.
You should not expect a buyer's agent who is not a QPIA to be able to buy a property which is necessarily appropriate for your financial circumstances and goals.