Most relationships involve mutually shared usefulness in addition to a mutually shared pleasure or satisfaction in reciprocal acquaintance and association. When the usefulness of one's friend exceeds, for the other party, the pleasure or satisfaction of association, the relationship can become polluted into a more disingenuous situation of feigned appreciation portrayed to grease the skids of manipulated objectives.
Clearly the benefits of mutual usefulness are a worthwhile advantage of a healthy friendship that can strengthen the bonds that otherwise tie. There is nothing inherently wrong with mutual usefulness.
Lines of trust can become blurred when usefulness erodes the relationship into one of exploitation and insincerity. Previously healthy friendships can easily devolve into manipulative pursuits of utility value or other social objectives in the absence of forthright disclosures of competing values, motives, and interests.