It's worth noting that the support for Adblock and Adblock Plus extensions is how Microsoft plans to offer an ad-blocking experience. Originally, some slides from a developer presentation made it seem as if Edge would have built-in ad-blocking; instead, it'll just support the feature from third-party developers. That's just how Apple and Google handle ad-blocking with Safari and Chrome.

While it's good that Microsoft is supporting more extensions, the company has a lot of work to do to close the gap with its browser competition. Most users probably don't use more than a handful of extensions (and lots probably don't use any at all), but those who swear by them likely won't switch to Microsoft's browser without replacements.