Why is Liston considered the most intimidating fighter when George Foreman had much more knockouts and more brutal wins?

Liston had a couple freaky KOs but he was not an overall aggressive fighter and many fights went the decision. Foreman on the other hand went out like a killer and clubbed his opponents to the death and has a higher KO ratio. Foreman was also considered invincible in his prime and Muhammed alis teammates feared for Alis life prior to the bout. ​​​​​​ So why with all this said in retrospect is Liston considered more intimidating than Foreman?