Hiring a literary agent is not something that a lot of people want to do. There are certainly scam artists out there that you’re going to need to avoid, and that’s an issue. There are also perfectly good literary agents who still will not manage to really get your book out there through no real fault of their own.
However, if you want to go the traditional publishing route, you need a literary agent. There is really no getting around that. You have to find a way to make sure that you can get the resources that you need for the sake of your book. You just can’t do that unless you have an agent. Even a lot of the people who have agents never get anywhere with traditional publishing. Publishers will rarely even look at a manuscript that isn’t represented by an agent and that does not have the support of an agent.
You don’t need a literary agent to get a book noticed in general, especially in the age of self-publishing. However, you cannot even try to go the traditional publishing route without a literary agent. You need to read reviews and try to get the representation that you need from a literary agent, who may or may not decide to represent you and who may or may not decide that your book is worth reading. To a certain extent, hiring a literary agent is going to feel like an audition before an audition, and that is one of the things that will make the whole process seem that much more daunting to everyone involved.
Hiring a literary agent is not something that you should decide to do lightly. There’s a lot of commitment involved to going down the traditional publishing route. Even working with a literary agent offers no guarantees, except that you will be working hard. You and your agent could try to sell your book everywhere and you still might not get anywhere. However, if you do succeed, you will probably find yourself getting ahead all at once in a way that would not be easy otherwise.