Why Pycharm gives warning on "simple variable usage" in .sh bash script? [duplicate]

Question

In Pycharm when we use variable e.g. $privateKey, we get the warning Simple variable usage as below snapshot and recommend us to turn to the syntax ${privateKey}

My question is why we get such warning? What is the risk to use simple variable like that?

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Answer 1

Thanks to @Whymarrh. One answer is as below.

since "$foobar" would instead expand foobar

My answer is to separate/distinguish $myVar and notInVar in string "$myVarnotInVar"

In other words

myVar=122

echo "$myVarnotInVar" # will print empty string "" since undefined variable $myVarnotInVar

echo "${myVar}notInVar" # will print 122notInVar