Use, service, advantage, profit, account, avail can all mean a useful or valuable end, result, or purpose.
Use stresses either employment for some purpose or end of practical value or the practical value of the end promoted or attained.
Service , though often interchangeable with use , is especially appropriate when the reference is to persons or animals or their work or actions <the horse was unfit for service —Scott > <render a service to a friend> Service often implies that the result of one’s act or works is beneficial.
Advantage adds to use the implication of improvement or enhancement (as in value or position).
Profit distinctively implies reward or the rewarding character of what is attained, and often implies pecuniary gain.
Account is used chiefly in fixed phrases. It is sometimes interchangeable with use , advantage , or profit , but distinctively it suggests calculable value. Sometimes it is nearly equivalent to importance .
Avail so strongly suggests effectualness or effectiveness in the end attained that the negative idiomatic phrases in which it is often found are equivalent to ineffectual or ineffectually .