It depends on how thorough the blacklist is, but I usually avoid using those, because I fear I may be losing interesting discussions that only tangentially mention the topic I’m blacklisting. Or maybe they are discussing that topic from a different perspective that I may find interesting.
It’s not like Lemmy has so many discussions to choose from, anyway. Among the communities I’m subscribed to, the most active ones only have three or four discussions per day, at most. I don’t feel like a (albeit temporary) blacklist is useful when there’s so little content to parse through. If there were a hundred posts per day, and I was interested in hiding half of them to better highlight the ones I’m interested at - but with so few posts, I can ignore them just fine without the help of an automatic blacklist.