I have a server that spools off the entire New York stock and options market every day, plus Chicago futures, using Lz4. But when we copy to archive, we recompress it with Zstd, in parallel using all the cores that were tied up all day.
There is not much size benefit to more than compression level 3: I would never use more than 6. And, there's not much CPU benefit for less than 1, even though it will go into negative numbers; switch to Lz4 instead.
If you know your use case well and are sure the situation won't change (or don't mind swapping compression algorithms when they do), then lz4 still has a solid niche, especially where compression speed matters more than decompression speed. But in many if not most cases I'd say it's probably a kind of premature optimization at this point, even if you think you're close to lz4's sweet spot.