Simple Delivery is here to stay. There are still glitches which eBay are working on, slowly.
Do you know you can choose a different delivery service and ignore the SD label? There are many posts about how to do this. Please note, if you have Buyer Pays for the label, they will be automatically refunded within 30-days. If you paid for SD, then you have to request a refund.
There are benefits to SD for your Buyers. They pay less for Royal Mail Small Parcels than without it. It is automatically Tracked 48 service with £750 cover.
There are benefits for you with SD. If an item is damaged in transit or lost, eBay refunds your Buyer and you keep the money from the sale. Also SD protects you from Negative or Neutral feedback due to delivery problems.