That make a great deal of sense.
On a related question - Can anyone explain why, compared with other European royal families, the British royal family allows its members so much freedom to make their own decisions in relation to titles?
In recent history, I can recall only rare instances in other European monarchies where a monarch allowed members of their family to make their own decision relating to titles, rather than applying the laws or conventions of the day.
In the UK it seems to be a different story. Over Queen Elizabeth II's reign alone, Princesses Alexandra and Anne and their husbands were allowed to accept or refuse titles for their husbands and children, Prince Edward was reportedly allowed to pick Earl of Wessex over Duke of Cambridge as his peerage title, the Wessex and Sussex couples were allowed to refuse the conventional titles for their children, and the Duchess of Cornwall was allowed to use one of her lower titles. There are more examples to be found from earlier reigns, e.g. Princess Margaret's husband being allowed to make the decision about a peerage or Princess Patricia of Connaught being allowed to resign her title.
Why is the British Royal Family so idiosyncratic in this way?
My guesses:
(1) As the "fountain of honour" the Queen can choose to respect a family member's wishes regarding titles or not. She obviously chooses the former (at least in terms of choosing
not to use or accept a style or title. If Beatrice and Eugenie demanded that their children be HRHs, I believe the Queen would refuse).
(2) Peerage Titles: In the UK peerage titles confer not only a social status but also a
legal status. I could be wrong but I don't believe that is true in other countries. For example, until recently British peers were entitled to a seat in the House of Lords which still wielded at least some political power.
Because of this, it is possible that Angus Ogilvy and Mark Phillips were sensitive to the fact that in an increasingly democratic society, many people believe that a peerage should be
earned, based on the recipient's merits, and not simply awarded because he has married a member of the BRF. For example, Antony Armstrong-Jones was criticized for accepting an earldom months after his marriage to Princess Margaret.
Perhaps Edward was given an earldom rather than a dukedom because it was decided to create him Duke of Edinburgh once Charles ascends the throne (assuming Philip has already died). I suspect the decision may also have been a part of a "slimming down" effort due the RF's unpopularity at that time, in the wake of the failed Wales & York marriages and Diana's death. In a somewhat similar fashion, Infanta Cristina of Spain was deprived of her ducal title as a result of her involvement in the Noos scandal.
(3) HRH style: Again, I believe the reason it was announced that Edward and Sophie's children would not use the HRH might be due to a "slimming down" effort on the part of the BRF as well as the fact that Edward and Sophie did not intend to be working royals.
(4) I suspect the BRF is currently rethinking their approach to peerage titles as well as George V's LP regulating the HRH. For example, under the present rules/customs Prince Louis will be awarded a dukedom and (assuming his father becomes King) his children will be entitled to the HRH. But his older sister Charlotte, who precedes him in the line of succession, would not become a Duchess nor would her children inherit her HRH.
But because the Queen is (1) a traditionalist and (2) very conservative, rather than simply overhauling the system (as the Luxembourg royal family has done) she prefers to deal with the issue on a willy-nilly, case-by-case basis.