DAHDI – is it needed?

Running a pure IP setup, no hardware involved. I keep seeing that I need DAHDI to use as a “timing source” for things like conferences and echo cancellation. However, my setup seems to be working just fine without it. As with many Asterisk questions, it’s very hard to find any information for current versions. What exactly does DAHDI provide? Is it still necessary?

Running Asterisk with FreePBX 2.9 and 2.10. Thanks!