The first version of the FMX framework was released in 2011 and already had one of its fundamental features, that is, the rendering of the UI was done completely from scratch, using the GPU. At the time, the GPU already supported technologies such as shaders (https://en.wikipedia.org/wiki/Shader), opening up a way to implement high-quality vector graphics, also considering the CPU growth in terms of computational power.
It became possible to build complex UIs, decorated with stunning effects and transitions, reaching the same appealing visuals typical of technologies such as Flash (the leading technology in modern and good-looking UIs, at the time). Given that WinAPI (thus, the VCL) and the new (at that time) .NET alternatives - Windows Presentation Foundation (WPF) were not covering the capabilities, the development team of FMX saw a great opportunity to build a new framework and, thankfully, they decided to take the chance.
This was the beginning of the framework having the opportunity to control every aspect of the UI implementation, opening the possibility to strongly abstract the UI from platform-specific controls and capabilities, but the number of controls available was limited and the first version of FMX was not really able to catch up with the same level of functionalities offered by the VCL on Windows.
The major new feature added with FMX 2 was bitmap styles: building a rich vector-based UI had a huge impact on performance and, at the same time, it was hard to implement some of the required components and peculiarities of the UIs. Adding the bitmap style capability moved FMX into the position to build effective, good-looking (pixel-perfect was the motto at the time), and performant applications, still keeping strong abstraction (through the style concept).
Even though it may seem a step backward (from pure vectors to bitmap styles), one should consider that most computer graphic evolution over the decades has gone in a direction where bitmaps were a central part of the game, thus most operating systems and drawing technologies are very familiar with bitmap (raster images) handling and have been optimized for that.
In the next couple of sections, we'll explain why the FMX framework is to be considered an application framework rather than a merely visual framework. It is important for you to properly understand that the general approach toward cross-platform application development has a lot to do with the visuals (we are focusing on visual applications), but there's much more to consider.