As you might see, I didn't have plans to pull for Caesar. I said to myself, if I didn't get her in 20 pulls, then there's no need to continue. Unexpectedly, I got her in 20 pulls and her weapon in 40 pulls (my first S-rank W-Engine, tho).
DISCLAIMER: Caesar is only half-upgraded since I didn't have plans to pull for her.
First of all, I want to ask you not to let the hype train decide for you. If the question is whether she is necessary to finish the endgame content. The answer is no, she isn't necessary, especially if you have Jane Doe and Seth. I still believe that Jane Doe alongside Seth was a more valuable banner for Critical Node since this duo doesn't require anyone else to have overwhelming results. However, even when my Jane's team didn't have any issues with the 5th stage of Ambush Node, my second team was struggling really hard. With the team of Zhu Yuan, Koleda, and Nicole, I was only able to get an S-rank after about 20 stressful tries. As soon as I pulled for Caesar and half-upgraded her, I finished the second half of the 5th stage on the first try two times in a row. Her shield value makes the Nest Blitz Mode and Ambush Node feel like a morning walk, removing any significant challenge. I should also add that her W-Engine can be replaced with Anby's or Koleda's W-Engine. Her ATK buffs for the team are also cannot be underestimated.
Summarizing, Caesar provides a huge addition for quality of life and simplifies the part of the game where survival is critical. Caesar is your guarantee that your team won't die, no matter how hard the game might become. Caesar can suit many teams, from Jane + Caesar + Burnice to Piper + Caesar + Lucy. If you invest her fully than she will become your wife, your life, your partner in crime. However, if you don't mind dying and trying again, you've already finished all endgame content, your have other team build in mind - then you can continue to stay strong for Burnice, Yanagi, Lighter, Myabi, Harumasa or whoever else you wanted to pull. 
From myself, I'd like to add that the gameplay part is very important from an aesthetic point of view, since this is what you see on the screen 90% of the time. If you enjoy her gameplay, then don't hesitate to pull for her. If not, then maybe she isn't for you, and you wouldn't enjoy her as much as you could. Have a great day. 
