Some people really like doing this; for varying reasons. For the people that are fighting illnesses, such as cancer, diabetes, etc. I think it is important for them that they test.
I am doing Keto for the health benefits (for sure) but also for weight loss, and I have heaps to lose still. I have been doing Keto since February; more properly and strictly since May though. I have never used any testing strips or machines. If they were free, I probably would. For me it is about cost, we are on an extremely tight budget already, so I cannot do it so I don’t.
I think if you can afford it and it makes you happy or it you have other medical reasons to do it, then go for it =).
Keto is a very diverse way of eating. There are the basics of keeping to 20 grams or less a day of Carbs, NO sugar, and getting adequate proteins, healthy fats, and drinking lots of water and keeping your Electrolytes and salt up. Beyond that, there are many variants amongst people. Some do strict Keto, some do lazy, some do really lazy. Different ways work for some, and others have a different way that works for them.
You will figure out what works best for you as time goes on. Just follow the basics, especially the 20 grams or less of carbs a day. If you want to track, which makes it easier, you can download cronometer.com a free app to use. It sounds like you are doing really well already and on track, so keep at it and best wishes in your journey!