The absence of Google services is the main reason for that but Huawei says it's ready to launch its substitute - HMS (Huawei Mobile Services). The services would be ready to launch next week and the first phones to run it are the Honor V30 and V30 Pro. They will debut in Europe packed with home-baked services including Huawei ID, Huawei Mobile Cloud, Huawei AppGallery, Huawei Video, Huawei Themes, Huawei ScreenMagazine, and Huawei Browser.
We ought to anticipate that HMS (Huawei Mobile Services) to make it to other Huawei and Honor phones too and we suspect the Mate 30 Pro would be one of them. Still, you'd have to find a way to live without GMS, which might be a test.