It's also one.of.the.worst.ideas.of.all.time to put apps on SD cards.
eMMC storage, the internal storage, moves things around from save to save, to extend the life of the storage (like an SSD does). And, if a section goes bad, it can "pair off" and use an unused chunk of storage to replace the bad part.
SD cards don't do that.
Both, eMMC and SD, are rated by the number of writes they can take. It's huge, but it's not infinite, and eMMC can take orders of magnitude more.
Android apps keep their current state at all times, because Android can kill an app, then when you bring it to the foreground, Android can load it again and tell it to start from where it left off, so you never know that it was killed. If an app is moved to the SD card (or the SD card is formatted as internal, and an app gets installed to it), and the piece of code that saves the current state ends up on the SD card, and the app is changing constantly, that's millions of writes to the SD card and ... goodbye SD card. Early failure.
Store files on the SD card. Pictures,music, videos, documents, etc., etc. Stored once, written once. If the phone is too small (in internal storage), you need a larger phone. (That's why, even though a phone with over 20GB of user storage was really enough for me for a few years, when I upgraded phones I went for 128GB [which gives me about 108GB of user storage]. I want the phone to last. with 108GB available, it will last until I get sick of it, or it can no longer be used, because voice will be 6G and data will be 8G, and the phone doesn't do them. My old AT&T [actually marked Cingular, which is what AT&T Mobility really is] V551 was a great phone. If there was a risk of losing or damaging my phone, I'd throw it into a pocket and leave my daily driver home. It does 2G voice and text. AT&T now does 3G voice and text. Oh, well. But the phone is 14 years old, so it doesn't owe me anything. When my Pixel 2 is 14 years old, I will have gotten rid of it long before.)