To a person with almost no artistic talent, UI Semantics was a god send as it did most of the formatting as well as design for you. It could help you neatly design icons, images, div boxes and organize them without the pain of calling position or moving over elements by 1px everytime to get it right. However, using raw HTML and CSS can give a lot more freedom with the options and tools they provide.
Say you were baking cookies one day and you decided that you wanted them in a certain shape. You essentially have two options here, risk it by trying to make a cookie mold yourself or shaping the cookies yourself or hope to find a cookie mold online that fits your exact design or find something similar. If you try to risk it by making the mold yourself or shaping them yourself, you might fail and end up with some horrendous shape or end up making something beautiful. On the other hand you can scour the stores maybe finding the perfect mold but maybe having to settle for something similar or even nothing at all. This example illustrates the two sides of HTML and CSS as well as UI Semantics as you could try shape out the perfect website with the freedom from HTML and CSS or use the formats in UI Semantic to already shape out most if not all of the elements of the page for you.
However when designign a website I personally think that it mostly comes down to artistic design with some coding sprinkled in there. You have to ask yourself does this color match this one, would this div box look out of place here, how can I move this element to a certain place? While all solvable with HTML and CSS, what if a person doesn’t have that kind of artistic ingenuity, it is much easier as well as nicer if they could have most things formatted for them. As when I made my first web page using HTML for a school project, it looked terrible, something akin to a kids drawing compared to what some of my ohter classmates made. When I first tried out UI semantics, I thought it was very helpful as I didn’t have to worry too much about centering div boxes a certain way or controlling the margins and paddings to look perfect, it was already done for me.
Having a good balance of HTML and CSS along with UI Semantics is one of the best choices for everyone in my opinion regardless of artistic or architecture talent. Say someone already had their whole website planned out, where to put the div boxes, images, paragraphs, inputs, they might find that there is an easier way of placing them using UI Semantics rather than eyeballing it through position or floats. While people who don’t know where to start are given frameworks to build off of with UI Semantics and they can add a little of their artistic touch with HTML and CSS, whether it be changing the color or moving some elements to the side. UI semantics is overall a great tool to use with HTML and CSS.