I tried this for the first time a few months ago and liked it. But it was only for a bag of cat food. I can imagine that errors do happen, so 1 should check their items before the employee leaves. The plus side to doing this, especially at Walmart is you only buy what you need since you're not browsing the aisles.
What I have been doing more recently is ordering what I need online and having it shipped (free shipping) to me. With sensitive places, I choose to do this for now. Just need to adjust to not waiting until something is empty or near there before you order. Rule of thumb is, if it's half gone, reorder.
I've used curbside pickup at Target in Kapolei a few times, twice at Ace Hardware in Wahiawa, and once at the Mililani Walmart. Not a single hiccup.
I also recently made an online purchase at Home Depot in Pearl City. They have a system where they place your order in a locker at the front entrance. You're emailed an order number and a QR code. Show that code to the electronic reader, and it unlocks the locker that contains your items. No need to go inside the store.
Anything that won't fit in a locker will be waiting for you at customer service.
Some of these methods existed before, and others were implemented because of the pandemic.
I don't see any reason to fear problems. If they happen, you can relax while they fix it for you. It's not like Amazon where you have to ship things back and wait for replacements.
There's a hoarding mentality here on island. If something is on sale, you better get it then or you might miss out. I usually shop sales, so if I will need something soon-ish, I go ahead and pick it up until I run out of the old. That satisfies the extra time required if mail-ordered, and saves me money since I can't always find discounts when I run out.
I'm also an IT guy. Always have a backup.