What is the meaning of 'all hat and no cattle'?

English as a Second Language English Teacher Explanations (ESL Tests)
1

English Language Tests, Intermediate level

ESL/EFL Test #301 [color=blue]“English Slang Idioms (23)”, question 9

Sure, he drives a nice truck, but he’s all … and no cattle. He lives with his mom and has no other assets.

(a) brand
(b) grass
(c) land
(d) hat

English Language Tests, Intermediate level

ESL/EFL Test #301 [color=blue]“English Slang Idioms (23)”, answer 9

Sure, he drives a nice truck, but he’s all hat and no cattle. He lives with his mom and has no other assets.

Correct answer: (d) hat

Your answer was: [color=red]incorrect
Sure, he drives a nice truck, but he’s all grass and no cattle. He lives with his mom and has no other assets.
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What is the meaning of “all hat and no cattle”?

2

It’s an expression that refers to someone who wants to represent himself/herself in a certain way but he/she isn’t really like that.
In this sentence, the man drives an expensive truck (so he wants to appear wealthy) but he has no other assets (like a house etc.) and lives with his parents.