Almost every Android flagship these days has a microSD slot (we're looking at you, Google), which means that for most people, storage is easily expandable. Not only are microSD cards simple to use, they're also getting more and more inexpensive. Case in point: this 128GB Samsung EVO microSD card retailed for $109.99 less than two years ago, and now you can pick one up for just $33 on Amazon.
You could make the argument that microSD cards are less useful than they once were thanks to free services like Google Photos, but what if you live in an area with terrible mobile data and/or WiFi? What if you want to preserve the quality of high-resolution photos or 4K video? And with a whole 128 gigabytes, you'll be able to store around six hours of that lovely 4K video (48MB/s should be able to handle it on a mobile device).
Now, onto the price: $32.90 is lower than we've ever seen for this particular card. The regular price may show as $39.99, but according to CamelCamelCamel (a service that tracks Amazon prices), the selling price (not the original price) for this card was nearly $48 just two weeks ago. There's clearly been a price drop there. For comparison, SanDisk's 128GB Ultra card is selling for $41.54 right now, although to be fair, it advertises a higher 80MB/s transfer rate.
If you're interested, check the source link. It's unclear how long this sale will last for, so you may want to hurry.