The one difference: there is no private integrator here
There are two ways to issue an e-Arşiv invoice: through a private integrator, or directly through the tax authority's own portal. This connection is the second. Your credentials are the user code and password you sign in to the Interactive Tax Office with; there is no third company in between, so no separate integrator agreement is needed either.
The user code is the 11-digit national ID number for sole proprietorships and the 10-digit tax number for companies. Which one you enter is determined by your business type; there is no choice to make between them.