If it was crocheting, I would get it, but woodworking is not an inexpensive hobby where the software becomes the top line item.
This here I would also use at my job whera I am a bit of a Jack of all trades so once a quarter I need to sketch some model of something to see if it would fit or not. Example would be right now i need to sketch a simple collision protection for a outdoor cable tray (for Solar Pannel Strings). Gonna not take me longer than an hour. I do not use it enough to justify spending 40 Bucks a Month 4 times a year.
Its just that often times, even us programmers seem reticent to pay for software even though we happily throw dollars across the counter for a sugary coffee somewhere.
I know of sketch up primarily from DYI magazines, hence the assumption.