There's a pattern I keep running into where the "standard" advice turns out to be way more than what's actually needed. People online say you need a foot of soil for tomatoes, but tomato roots mostly feed in the top 6 to 8 inches anyway, so the extra dirt is just sitting there not doing much. Same thing happens with mattress shopping, where everyone swears you need to spend a grand, or with cooking gear, where people buy ten knives and use one. We tend to copy what we see others do without stopping to ask what the plant, or the task, really requires. Your side by side test is the kind of thing more people should do instead of just repeating what they read. Spend the savings on water delivery, since that actually reaches the roots.

My silicone mats do the same thing with chocolate chip cookies but they work great for stuff like sugar cookies or shortbread that hold their shape. The trick for me was chilling the dough first and putting the tray in the fridge for like 15 minutes before baking, that stopped the spread for the most part. But honestly for $40 you could've bought a lot of parchment, and parchment still gives you that little bit of grip that silicone just doesn't have. Your mileage may vary though, some people swear by the name brand mats.