Euclid and Euclidean geometry are still studied to this day because his contributions laid the foundational framework of mathematics. His postulates are set the ground work for more logical deductions to come later on. Euclid starts his work with basic definitions and every concept to come next is built on the previous one, making it rich in simplicity. In my opinion, any work rich in logical reasoning and simplicity will always endure through the centuries.
Euclidean geometry is not only simple, but also rich in beauty. I remember introducing my student to Euclidean geometry and her enthusiasm to come to class everyday was tenfold. My student appreciated the universality of Euclidean postulates and found it very inspiring that these concepts were intuitive rather than complex. When I myself was introduced to Euclid in grade 8, I thought his proofs were logically harmonious, almost like a poem. The use of logicals reasoning to prove geometric concepts is the reason why his work is considered beautiful. One cannot forget that it was this beauty that inspired great minds like Newton and Descartes among many others. Euclidean geometry also embodies visual symmetry and structure using circles, triangles, and polygons.
Euclid's Elements and the appreciation of its beauty come from its ability to combine logical rigor with simple, universal truths that resonate both intellectually and aesthetically. It has provided a basis for how to think, argue, and deduce that has shaped mathematical thought for centuries.