Job titles seem arbitrary.
No orientation to consulting for those who've never been in that role. The "on the job" learning for them is then a burden on the Lead Consultant at the client.
If, as a consultant, you're also asked to sit in an Interim seat at the client, they often look to you to fully act in that role and participate in the staff annual performance reviews and salary changes for the entire department/team, PIP developments, interviewing candidates for open positions, employee engagement survey result remediation activities, etc. This not only adds a challenge to achieving your deliverables on time, but also blurs (for the client) who you are and why you're there.