Dailing by extension is a behavior that our customers and staff are very accustomed to. I expect most customers who are coming from other phone systems, ie. Nortel, RingCentral, and others are used to providing their extension to outside parties to call in to them rather than a bunch of random DID numbers. The July 2018 roadmap indicates that extension calling is available now (https://skypeandteams.blob.core.windows.net/artefacts/Skype%20for%20Business%20to%20Teams%20Capabilities%20Roadmap.pdf) but this is not the case. At least not for external callers calling into an auto attendant.
Rob W. commented
We are using Dial by Name for a small organization. Name recognition is NOT close to 100%. I am very concerned about the miss rate for a larger organization. We can't recommend product for implementation until dial by extension is available.
I reached out to a solution specialist for Teams calling to see if extension dialing was possible. He met with a Microsoft engineer last week and was able to confirm that "extensions are on the project roadmap for Teams, but are not yet currently available".
This is the final piece keeping me from a full switch to Teams Calling.
Martin Gonzalez commented
Are there any updates?
Can Microsoft confirm this? Our project is in crossroad due to this functional deficiency.
While voice recognition dialing is fantastic, however, it may not be able to recognize non-native English speakers