Sentence vs Word mining

I have been doing word mining for quite a while now, but as I begin to learn more and more abstract nouns, I've been considering using full sentences on my flashcards instead of single words.
My main concern with this method is that I feel like I will end up memorizing the context of the word rather than the word itself. For example, I may not be able to read 例, but if i see the sentence 難しい言葉を習ってる時、例文を読めば良いです。 I might be like ooh this is the sentence about learning hard words, i know this says れい, but then when i see the singular character in the wild I will not be able to read it.
The other worry is that it will hinder my ability to memorize definitions since I will have the example sentence to figure out the context without actually memorizing it.

Can people who have experience doing both or one give me their input, and if they actually experienced these things I fear.

by Comfortable_Lamp