[GNC] Trading accounts

[Fred Tydeman]

Over the past several months, I have been importing Quicken data into
GnuCash.  There is about 6 years of data and lots of transactions.  Besides
normal income and expenses, that data involved many different stocks and
many different currencies.  Recently, I saw a reference to "Trading"
accounts.  I have now enabled that feature.  Based on reading
https://www.mathstat.dal.ca/~selinger/accounting/tutorial, I believe that
my old transactions that involve currencies (and maybe stocks and other
assets whose value varies) were done wrong.

Do I need to redo old transactions involving currencies?
Do I need to redo old transactions involving stocks?
Do I need to redo old transactions involving any assets whose price
varies?  This probably depends upon the asset, eg. no for Real Estate.

Is there an easy way to fix the mess I have created?

Aside:  I do not recall any mention of trading accounts in the Tutorial
early on when it talked about setting up the Chart of Accounts.

What is the reason that Trading accounts are not turned on by default?