As an example, almost non of us in this forum are eligible to pay the Zakah according to shia Fiqh, since very few of us own livestocks, gold, silver etc, even if we are millionaires and billionaires. But most likely, we are in the condition pay "Khums". To me, this doesn't fit in well with how the Quran has emphasised Zakah soooo much on every person, while it has never mention anything about Khums. Do your own research, you'll be surprised!