I may have gotten it wrong, but I guess it depends how you interpret the language. 'Clear and Obvious' error....what does that even mean?
Goals
A close offside decision is the most common reason for VAR being consulted after a goal has been scored, but shirt-pulling and other infringements can cause goals to be chalked off.
NB. The concept of 'clear and obvious' errors does not apply to offsides. A player is either onside or offside - you cannot be a little bit pregnant. So even if a player is offside by a matter of inches, the goal will be ruled out.
Penalties
The most subjective and arguably problematic area. Penalties can be awarded or rescinded using VAR if there has been a 'clear and obvious error' in the original decision.
Straight red cards
Violent conduct and dangerous tackles can be penalised using VAR. Second-yellow cards cannot.
Mistaken identity
If the referee sends off the wrong player, such as the famous incident with Kieran Gibbs and Alex Oxlade-Chamberlain in Arsenal's 6-0 drubbing at Chelsea in 2014, that injustice can be repaired.
The system is restricted to these areas in order to minimise disruption to the flow of the game.