pg_sleep() inside plpgsql block - pro & cons

Hi!
There is second time I see that somebody uses pg_sleep function inside
plpgsql block. This case is quite similar to the last one - it's some kind
of wait for data to be loaded. After pg_sleep there is a check if some
condition is true, if not procedure goes to sleep again. As a result an
average duration of this function is 1,5h...
I'm trying to gather pros and cons regarding using pg_sleep this way. What's
coming to my mind are only 2 cons:
* clog contention
* long running open transactions (which is quite good described in here:
https://www.simononsoftware.com/are-long-running-transactions-bad/)

So maybe you'll add some more to the list?

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