Would a cheap $15 ssd like this be good for a rpi?

Hardware
21

Completely different use case and you misinterpreted your mileage to be valid for a complete different task (which is it not!) :twisted_rightwards_arrows:

If you use such cards for continuous recording like the seller expects (“Full HD (1920x1080) video content recorded at 26 Mbps”) the write amplification factor will be probably always be 1. :raised_hands:

So for every (m)byte requested from the OS to be written to storage also exactly one (m)byte is actually written to flash. That’s great because no waste of valuable flash cells. :diamond_shape_with_a_dot_inside:

But wait, now we don’t write 26Mbps contentiously (and the limited warranty might is void) but instead we let HA do it’s job which consists of writing a very small amount of data but that quite regularly. :bar_chart:

As an example if HA(OS) wants to write only 1 byte it will cause huge write amplification because it’s not possible for the flash storage to only write that 1 byte. Instead a whole page worth of (e.g) 16kbyte gets written/wasted/worn for that tiny little byte. :hammer:

Now we can do the easy calculation and we find out that the write amplification factor would be 16.000 (yes, sixteen thousand) in this case. :put_litter_in_its_place:

So while @ogiewon got good mileage using this cards for the proper task with a WAF=1 they are NOT RECOMMENDED for the use with HA or any other DB application and should be avoided :warning:

The correct sd cards one wants to use are listed in the docs and what only matters is that they have the A2 class (beside probably using a product from a flash manufacture too).