Hey, this provides a little something you might not have had on your own *if you have put in the work*. That is the takeaway. I use it occasionally for specific training workouts that I know will simulate race efforts. I definitely use it on race day. What matters most is the work you have put into your base training so that when the time for a marginal gain oriented product like this comes, you have both variables working in your favor. Slathering this on as some sort of substitute or supplement for training is probably going to leave you disappointed and slimy feeling.
You're probably fine without these, but the motion plates make the trainer better to use. And regardless of how poor of a value it is to pay over $200 for some plastic feet for your trainer, you'll most likely never want to ride without them once you set them up. They make the experience on my 2T a lot more enjoyable. To be frank, I think my nether regions hurt less with these installed. My biggest gripe is that they are only connected by some relatively weak magnets and will fall off easily if you try to move or fold the trainer with them on. I've also seen reviews saying they don't do well for sprinting...haven't tried it personally, but I've done some standing efforts on hill climbs and they do just fine.
The best cream you can use to prevent chaffing and rubbing to the inner loins that grip your saddle on long days where sweat and salts by friction rub you as raw as a newbie on Cell Block 6! This stuff imparts a cooling menthol type feeling quickly upon application but dissipates very fast. I apply directly to my skin rather than rubbing on the chamois pad like some do or at times, the manufacturer suggests. Truly a needed product just like supplements for any cyclists. So do yourself a favor and buy a jar today.......a little dab will do you!