Some people may not understand what the reason is for taking either a different payout option when making a post. Or maybe they don't even know how they payout differently in the first place.
I had a comment last week (or at some point recently) where someone was asking why they would choose 100% vs. 50%/50% payouts. Once you understand, you can make a better choice on how you want to be rewarded.
Choosing reward options
Default (50%/50%)
This is the default payout option as you might have noticed when you first posted.
What does it do?
When the 'potential payout' gets issued after 7 days (used to be 1 day), you will receive at least 75% of that payout as an author. Of that 75% or more total, you will get 50% in SBD, and 50% is STEEM that is the equivalent of the 50% SBD value. If STEEM is worth less than SBD, you get more STEEM than SBD. If STEEM is worth more than SBD, you get less STEEM than SBD.
Why choose it?
Choose the default payout if you want to cash out more quickly. You can transfer all your SBD out and do something with it like convert to BTC, but you can't transfer all your STEEM at the same time as it takes 3 months to withdraw it all.
Choose the default option if you want to keep a near $1 value for half of your rewards. If STEEM goes down in value, your SBD won't as it will stay near the USD $1 value.
Power Up 100%
What does it do?
This is where you choose to "Power Up" all your rewards from the post and get paid 100% is Steem Power.
Instead of getting some SBD pegged to the USD, you will only get Steem Power. Steem Power can't be withdrawn quickly like SBD or STEEM, as you need to Power Down for 1 week to receive 1/13th of the SP, and for a total of 3 months to receive it all.
Why choose it?
Choose the 100% payout option if you aren't concerned with needing to withdraw much of your rewards quickly.
Choose the 100% payout option if you think STEEM will be higher than the SBD value of USD $1. If you think STEEM will stay above $1, or go higher, then taking the 100% payout option might be best for you. If you think the opposite -- that STEEM will go down below $1 -- and will want to withdraw some money, then maybe you want to go with SBD to keep that $1 value when you need it.
Choose the 100% payout option if you want more Steem Power to give more rewards in your upvotes. Your vote has more weight to it when it has more SP.
You can tell who has made a 100% payout post by looking at the title of their post indicated by a Steem symbol 
Like:
Pretty short and simple once you understand it.
It's up to you to choose how you want to handle your rewards. Each payout option has its pros and cons.
Good luck in your decision :)