Perhaps it would help if I explained my reasoning behind calling it a critical situation throw - there are after all many words I could have chosen and may still choose to replace the word critical.
And before I continue these suggestions are for resolving player character actions in situations that the referee and players end up placing the characters in; the referee still has all their usual procedural tools and rolls (wait 'til you see how to use the reaction table

).
To my mind if the sum total of character skill, experience (prior history), attribute and tools are taken into account then many tasks that later rules suggest are simply a waste of time picking up the dice and are more likely to result in eventual failure than success.
If a player and referee can agree that the way the player describes the character's actions plus the above factors allow their character to achieve routine stuff then do not bother rolling.
Hence it follows that it is only situations beyond the routine that require the dice to be consulted. I chose the words 'critical situation' because the outcome of the situation should have an impact for good or ill.
I could have chosen 'stressful', 'difficult', 'challenging', 'important' 'portentious' and may well swap to one of those, but the fact remains the dice are there to resolve key situations in the game.
If there is uncertainty about the outcome then you roll the dice.