Shoujo Ai is a bit of a useless tag, especially given the ambiguity of it. When the tag covers both friendships between girls (e.g. https://mangadex.org/title/22955/nettaigyo-wa-yuki-ni-kogareru) and romantic relationships between girls (e.g. https://mangadex.org/title/24924/hana-ni-arashi), what exactly is the tag accomplishing? The tag fails to accurately convey to the reader the nature of the story.
On the topic, MangaDex writes about Yuri:
"Japan typically uses this single category for all forms of these relationships, sexual or not. In the West, the term Shoujo-ai categorizes stories that focus on the emotional aspects of the relationships, while Yuri categorizes more of the sexual aspects and explicit content."
I think the important thing to note here is that Japan uses this single category for all forms of these relationships. The definition of how "the West" sees it is questionable at best. This has long been a source of debate, with "Shoujo Ai" being especially criticized by those who are aware of its origins.
Given that MangaDex has the "Ecchi" and "Smut" tags, as GoggledAnon mentioned above, there is no need to specify that an individual yuri story contains aspect of sexuality; there are other tags that accomplish this quite handily. Let's look at heterosexual stories for comparison, there is no distinction between "Romance" and "Sex Focused Romance," because we have the Smut and Ecchi tags to do that for us. Why does Yuri need this distinction, when straight relationships do not?
Not to mention that MangaDex thoroughly fails to adhere to their definitions of the tags. Tsurezure Biyori (https://mangadex.org/title/22831/tsurezure-biyori) has a yuri tag, but the story has a total of two kiss scenes over 17 chapters, and nothing further than that. Is this story focused on sexual aspects and explicit content? Yuki and the Authoress (https://mangadex.org/title/32306/yuki-and-the-authoress) similarly has very little focus on sexuality, yet it has a Yuri tag (and no Shoujo Ai tag!). I'd assert that the separation of "Yuri" and "Shoujo Ai" creates more confusion than it solves.