The necessity of CRM system?

If there are several people all talking to customers at different times, a CRM system that allows anyone to make notes of each interaction means it does not matter which person the customer speaks to next time - each person can see the previous notes.

That means customers do not have to re-explain problems or requests and they get a better impression of the business.

If it's just a one-person business, or each customer only talks to a certain person,  you can likely remember what each customer needs so no real point.