Based on the description of the spell, it looks like you can take someone's memory for 8 hours. does this mean you steal the memory or just copy it. based on the flavor text of cards like Nightsnare ("Ravnica would be safer if mere coin was all the Dimir could steal."), Never Happened ("Dimir assassins have the precision to slay a single memory.") and Thought Erasure ("It’s truly the highest honor, isn’t it? To be remembered? Pity for you." implying that the memory is gone forever).

This leaves me with three questions

1. does it steal the memory or just make a copy (flavor text says steal)
2. why does it only last 8 hours (or until you use it again), stealing someone's memory for 8 hours doesn't sound that effective
3. flavor text implies them being destroyed, how do you destroy them?

As a solution to these, I would design a homebrew spell that can find and remove thoughts and have Encode Thoughts be a sort of mini version of this spell, for emergency use when out of spell slots.

Another option would be to use homebrew to increase the duration to something like a month (although this doesn't address the destruction of memories).