Recurring payments and revenues (alias "Repeating Transactions"), which are defined by category, are in part already a substantial component of a budget.
It would be more functional (and correct I think) if the budget could be built in part from these, related to their frequency and categories, therefore complemented by the values of the estimated expenditure or revenue, by category and subcategory.
In this way, since I believe many people use the repeating transactions, the budget becomes more faster to build, practical and more functional (IMHO).
It will have to be only considered to exclude the operations defined as "Transfers" which aren't to be considered incomes or expenses.
I'm a new user, very satisfied from this nicely solution, and I hope it will be more implemented, but maintaining its simplicity.
Many thanks to the 3d.