You're not really getting this are you? From the same article:

"It shows the royals are playing an active role in the democratic process and we need greater transparency in parliament so we can be fully appraised of whether these powers of influence and veto are really appropriate. At any stage this issue could come up and surprise us and we could find parliament is less powerful than we thought it was."

Royal consent is exercised on advice of the monarch's ministers; it's quite possible for the monarch to decide for themselves, which is a real danger.

Terbius said:

"our Head of State is a Constitutional Monarch with no executive power"

She doesn't need executive power, that's what the government are for. The royal prerogative still exists and even now only the monarch can dissolve parliament. Furthermore, the lack of executive power doesn't stop the royals form abusing theirs as they meddle in the democratic process, as shown by Prince Charles and his Black Spider memos; that sort of lobbying is an abuse of power.