Success rolls: effective skill below 3

[Flinx]

Hello,

I am in the process of learning the basic rules and have just stumbled on the following (B345):

You may not attempt a success roll if your effective skill is less than 3, unless you are attempting a defense roll […]

It is not that this rule is not clear, I am just wondering why it exists and if I am overlooking any implications. Except for defense rolls as mentioned, this reduces the rule “3 and 4 are always a success” to “if your effective skill is 3, 4 is also a success”. And the odds for effective skills below 3 are so discouraging that it seems pointless to forbid it. If a player wanted to try something with an effective skill of e.g. 1, as a GM I would just say “You know this has only a 1.85% chance of success and a 50% chance of a critical failure, are you sure?”

But perhaps I am missing something here. Let me know if you think this is a rule that can be ignored without any impact.