Is it worth adding obviously “rotten” clients to CRM?

Question

CRM

The question has been tormenting for a long time - is it worth fixing obviously inadequate clients somewhere (whether it be CRM, notepad, etc.)
If you make it, a swelling customer base is created and a ghostly hope for a client who may someday (never) order a service.
But since we are a small business, we don’t need such fraud, it’s better to lead normal (potential) than hopeless "clients", what do you think? Maybe I'm mistaken, then in detail - in what exactly and how to work out such clients? (although often, in 99% of cases they are not financially interesting to us)

Answer 1

Costs. With a tick "rotten".

Answer 2

all these accounting systems, incl. CRM is set to collect data on which you can further analyze.
ps:
suddenly your manager is "rotten" and does not know how to communicate with the client?
or having accumulated information, you can draw up the criteria for "your" client, and as a result, weed out "rotten" ones on takeoff.