It looks like Synchrony is doing away with the paper checks. Since I had one get lost in the mail a few years back I have to say this is definitely an improvement. 
Direct link from message: https://mycashbackinfo.com/faq/en/
Highlights:
Q. Will I receive a check for my Sam’s Club Mastercard Cash Back Rewards?
A. No, for your convenience, your Cash Back Rewards will be automatically loaded onto your Sam’s Club membership.
Q. What do I need to bring to Sam’s Club when I redeem my Sam’s Club Mastercard Cash Back Rewards?
A. All you will need is your Sam’s Club Mastercard.
Q. How can I redeem my Sam’s Club Mastercard Cash Back Rewards?
A. They can be redeemed at any U.S. or Puerto Rico Sam’s Club location. You may redeem them in the following ways:
AT A STAFFED REGISTER OR MEMBER SERVICE DESK
- Apply towards your purchases
- Make a payment on your Sam’s Club Mastercard
- Apply towards your Sam’s Club membership renewal or upgrade
- Get Cash Back
NEW THIS YEAR!
- Apply towards your purchase at any register including self-checkout
- Use your rewards over time on multiple purchases in-club until your rewards expire or are fully redeemed
Do we know if they are sticking to the $5 minimum that they had for the checks or now that they are doing it electronically no need to enforce a minimum?
@Remedios wrote:Lordy, they are mailing notifications in blue envelopes. The sky will fall
LOL... yeah, they actually started that a year or two ago.
I posted about it at the time, and you're right, that's a good way to give people "who know about things" a heart attack. 
Yea, got this email as well a few hours ago, and you beat me to it on posting! 
Definitely an improvement for sure! Thank you for posting
Definitely an improvement for sure! Thank you for posting
I received the email too. To me, this is hardly an improvement. Why can’t redemption options be integrated into the card management site, like almost every other credit card with a rewards program? It’s 2019! I mean I know the answer (going into Sam’s Club encourages shopping, thus the funds are more likely to stay with Sam’s), but it’s still an inconvenience compared to my other cards.
@Sharingan wrote:I received the email too. To me, this is hardly an improvement. Why can’t redemption options be integrated into the card management site, like almost every other credit card with a rewards program? It’s 2019! I mean I know the answer (going into Sam’s Club encourages shopping, thus the funds are more likely to stay with Sam’s), but it’s still an inconvenience compared to my other cards.
Yeah, I see your point, but like you say you already know the answer.
For me the improvement is not having to be concerned with dealing with a check that never gets delivered. It's amazing that my bill never fails to show up, but of course the check would have to go missing. The replacement process wasn't that bad (other than the wait), but at least this way it's no longer a concern.
I was pleased to see that cashing-out is still an option. It's not as important as it once was (back when my checks were $150+) but I still like getting cash over the alternatives.
^^
The new instructions specifically say that you can't use it online. You have to go to the store.