Eh, it depends how you define Linux. Android uses a modified Linux kernel, but most of what’s above that is different. By the point you’re at the application layer they’re basically completely incompatible.
Is it technically Linux? Yeah but it’s so different from a user’s perspective it’s best to treat them as separate imo.
When you normally delete a file, it doesn’t actually delete it, to save time it just marks the space as free, so any new files can be written into that part of your drive.
But the actual data just remains there until a new file is written to the storage.
SecureErase does the second part without making an actual file.
Normal delete:
File: 01010101 -> no file:01010101
Secure erase:
File: 01010101 -> no file:00000000