Looks like a targeted offer hence you have to call a specific number as only those employees have the training and access to this deal. Normally you would have to pay the taxes component in cash this is the first time I’ve seen it.
Bear in mind usually the exchange rate is very poor and could change often as they won’t even quote a guide price. I understand if someone has a few millions of Avios it could be a way to reduce the cash to $5.