For some examples https://www.metabase.com/learn/analytics/data-model-mistakes...
https://www.cultured.systems/2024/04/24/Soft-delete/
https://brandur.org/soft-deletion
Many more can easily be found.
Once you've gone through some time and due diligence you can contemplate actually deleting the customer data and account.
1. you might accidentally access soft-deleted data and/or the data model is more complicated 2. data protection 3. you'll never need it
to which I say
1. you'll make all kinds of mistakes if you don't understand the data model, and, it's really not that hard to tuck those details away inside data access code/SPs/etc that the rest of your app doesn't need to care about
2. you can still delete the data later on, and indeed that may be preferable as deleting under load can cause performance (e.g. locking) issues
3. at least one of those links says they never used it, then gives an example of when soft-deleted data was used to help recover an account (albeit by creating a new record as a copy, but only because they'd never tried an undelete before and where worried about breaking something; sensible but not exactly making the point they wanted to make)
So I'm gonna say I don't get it; sure it's not a panacea, yes there are alternatives, but in my opinion neither is it an anti-pattern. It's just one of dozens of trade-offs made when designing a system.