The bottom line is that people love cats because they need to express their love towards a significant other and the cat is a great partner in that respect. Everyone needs to love and be loved.
Each person will have their own version of the answer to the question in the title. There won’t be one simple, single reason. The main reason why people live with a domestic cat is for companionship. A lot of single people, living alone, live with a cat companion. They love their cat because they provide all the things that a significant other person might provide plus improved reliability and consistency. One excellent reason why people love cats is because they are always there for you. They have their predictable routines as do people and the routines mesh very well in many households.
People love cats for a similar reason that they love another person. They need the companionship and they like a cat’s character. Domestic cats do have personalities. They are individuals just like people. The more you get to know them the more you appreciate this aspect of their lives and behaviour. You can arrive at an incredibly stable relationship with a domestic cat. It is quite difficult to achieve that sort of stability in a person-to-person relationship. It does happen a lot but the predictability of felines is an admirable quality which feeds through into a very stable, loving relationship. It is an unconditional form of love from the person to the cat. There is lots of altruism in it.
The person provides security, safety and food and the cat provides companionship and entertainment. It is a well-balanced relationship which fosters love between the two parties. Of course, the concept of “love” is a tricky one. We don’t quite know what it means even in person-to-person relationship. It’s about chemistry but nobody can tell me exactly what that chemistry is. Nobody knows really whether cats love another cat or person. It is more about close, affectionate relationships and friendships more than that mythical concept called love.
Is it fair to say that when some people become fed up with people i.e. when they are elderly, they turn to a domestic cat companion as a brilliant alternative to a relationship with a person? This might be a fair comment.
There are obvious practical and physical reasons why people love cats. They are very cuddly, they have cute faces which can look like babies sometimes due to selective breeding. They feel nice to the touch. They smell nice like babies (nutty!). They make cute meows when they ask for food. They sit on your lap and keep you company and warm. They feel the warmth of your lap and like the friendship and reassurance they achieve through direct contact. The appearance of the domestic cat attracts a lot of people. The feline appearance and movement is graceful and elegant. In a domestic cat you can immediately relate to the wild cat ancestor. You have a connection with the wild, with nature. This is a connection which is often lacking in people’s lives. Therefore living with a domestic cat brings you nearer to nature which is healthy. This encourages you to love the cat.
In fact, it is a reason why there is a fascination amongst a section of society with exotic cats. These are either full-blown wild cat species as pets or wildcat hybrids. Wildcat hybrids are cats such as the Savannah which at a first filial is a highly exotic cat companion and an expensive one. You will need to adjust your lifestyle to successfully live with and look after a first filial Wildcat hybrid, in my opinion. But people love these cats for their appearance and status. The desire for status is a good motivator for love! But is not an enduring version.
The glamorous nature of the first filial wildcat hybrid, I think, detracts from the most important aspect of domestic cat ownership which is the loving relationship between the two parties. You don’t want a domestic cat as a status symbol. You want to live with a domestic cat because they are a loving companion to you.