Lexicon is a serif font originally created by Dutch designer Bram de Does, and most recently published by The Enschedé Font Foundry (TEFF). It's a beautiful typeface, whether it deserves its huge $4,996 is a completely different question.
So is it worth it? Well it depends really, would I ever pay the best part of $5,000 for a typeface, no. However to companies that spend millions of dollars per year on marketing, spending five grand on a typeface that's going to fit their branding perfectly really isn't that much of a big deal.
Most typefaces nowadays price their fonts cheaply to make their product more accessible to the masses, and in turn hopefully get more sales. Lexicon however takes the complete opposite approach - they price their product at a much higher rate to only cater to people who place an extremely high value on typefaces, and in turn make their typeface more exclusive.