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

Yes, it should last for a good long while, it really is dependent on how many writes are occurring every day. For example, hosting a large number of devices and keeping history in InfluxDB, is going to wear out the storage faster.

MicroSD drives don’t wear out in a matter of weeks. It usually take many, many months before trouble starts. I have recorded continuously to SD cards like yours in cameras, as those cards have lasted well over a year. The Samsung High Endurance cards have never failed in multiple years of use.