What are the key advantages of using dumb trainers for year-round training, especially when compared to smart trainers that can provide more immersive and dynamic workout experiences? Do dumb trainers offer any unique benefits that cant be replicated with smart trainers, or are they simply a more affordable option for those who dont need all the bells and whistles? Can dumb trainers still provide an effective and engaging way to train during the off-season, or are they better suited for casual riders who dont need to worry about precise power output and data analysis? How do dumb trainers stack up against rollers and other types of indoor training equipment in terms of their ability to provide a realistic and challenging ride experience?