It's a bit unreliable. But the main reason is that true blue lotus (Nymphaea nouchali var. caerulea, the species native to the Nile basin and popular in Ancient Egypt) is, more often than not, not what you find online. I believe most of the product sold in herbal shops comes from southeastern Asia, and that means it is most certainly not going to be the var. caerulea but the var. nouchali, which is a similar water lily but not real blue lotus. If you want the real deal, distrust cheap prices.
And why is that important? Because while both varieties have psychoactive properties, the "fake" blue lotus may be useful mostly to bring good sleep quality, which in itself can encourage REM dreams afterwards, but the real blue lotus consistently has a higher concentration of other compounds that can also improve dream vividness and recall.
So if we had real blue lotus consistently available, I'd say yes, it is a valuable plant for lucid dreaming (among other things). But the usual "blue lotus" found online is not too reliable. It's nice, but I wouldn't focus on it as a botanical to facilitate lucid dreams.