As a preamble I have to put in that I understand the importance of a watch different than for example Philips Auctions or many others -- I will write up the exact differences but in short: it is usually not the price that makes a watch horological relevant or important.

If so, then why is the Jaeger LeCoultre ref24001 an important one?

Well, it is the brands 1st (and super-rare) luxury Steel-Sportwatch; it is their counterpunch to electronic watches and at the same time the last Chronometer in their vintage era; and it seems to be the model for the celebrated and 90° flipped Vacheron Constantin Chronometre Royal ref42001 (!sic); now, this is what I call an important watch.