There’s probably a lot more like this but this is just the one that occurred to me today.
エッフェル塔 and バベルの塔 are not going to help me remember 塔. My brain will remember the kana and work from there and not even look at the kanji before it’s worked out what the word is.
I know that vocab is useful in its own right, certainly the notion that 塔 can be placed on the end of something to name a particular tower is useful. But you certainly don’t need two of them in that case, I’m pretty sure most people don’t talk about the Tower of Babel a lot… right?
In summary, vocab should be either effective at aiding memorizing the kanji or simply useful in their own right. Some things feel like they’re playing with that line a little too much.
That’s my comment!