Being logical may matter... but I don't think it's the most important feature, as I said. Creating a perfectly logical language doesn't make it obviously valuable to most people. The underlying premise of Lojban is, more or less, that the problem with natural languages is that they're too illogical. Lojban fixed that problem and, relatively speaking, no one cared.

Lots of people hear of Esperanto and decide to pick it up. Almost no one hears of Lojban and picks up. Lots of people are fluent in Esperanto. Perhaps no one is fluent in Lojban. Granted Esperanto had a huge head-start, but I don't think you can attribute its relative success entirely to that factor.

Lojban is still missing something, despite being perfectly logical. English, on the other hand, is flourishing despite being extremely illogical. English is one of the most successful and least logical languages on Earth. Lojban is one of the least successful and most logical languages on Earth. "Correlation does not imply causation, but it does waggle its eyebrows suggestively and gesture furtively while mouthing 'look over there'." - Randall Munroe

All I was trying to say is that being logical is not a panacea.