Ryanair's adverts (in the newspapers) are now quoting fares inclusive of taxes and charges.
I presume the logic in separately detailing taxes & charges as part of the booking process is to highlight just how much or how little of the total fare is being absorbed by govt taxes and airport charges. I think this is worthwhile and in the interests of transparency. If the UK govt for example is happy to impose higher taxes on travel, I think it is only fair that those who pay the taxes (ie the travelling public) are at least aware of their existence.
In my own business as an accountant, we always make sure to detail outlay costs (eg Companies Office filing fees) separately on invoices to clients. So do insurance companies who always detail the cost of the 2% govt levy on top of the insurance premium.