I hit this exact same problem of wanting to know if the things I was looking at were worth my time learning. It’s not easy to figure it with a dictionary etc (this is not just a HH issue, but with any word I found anywhere). I ended up building https://chinesefrequencydictionary.com/ to satisfy my need to know!
It lets you look up the character/word and gives you a bunch of information on how frequent it is. The SUBTLEX-CH rank of a word is the one to look at generally - it’s basically how often that word turns up in movie + TV show subtitles which very close to real spoken frequency (it’s not 100% accurate is it puts words like murder, lawyer, doctor etc really high because of all the murder mystery/hospital shows but it’s close). The 友愛 page shows that it doesn’t even get a rank in any of my lists. So this word, while it is in the dictionary, was never found a single time in any TV show/Movie … so yeah it’s useless to you outside helping you learn the characters.
But that’s actually what HH does - it doesn’t teach you to read, or to speak. It teaches you to recognise characters! You can keep 友愛 for character recognition purposes, or you can skip it because it’s a useless word outside HH.
On that note HH does contain every single character in the 2021 HSK3.0 curriculum. HH also captures most of the HSK words, but not all of them. The words HH does have are usually useful/common, but as you found out, not always. You can check out exactly what is missed/skipped here: List of missing HSK(2025) words not found in HH