When I mention it to people who don't make their own I usually get 1 of 2 responses. Either something along the lines of "I'm not that tight, I just buy it" or "I'd like to make some but I don't know how". There are of course the occaisional, subnormal outliers who say there's no need for mud at all. But we'll forget about them and their nonsense.
Now, I can't deny that it's cheaper to mix your own mud, much cheaper. But Leedasink is only a couple of quid for a tub, if you were doing it to save money you'd be better directing your efforts elewhere. I also know some people who aren't too tight to buy a tub, seem to use much less, and keep a tub for years, well past its useable life span. I can't be the only one who's had boat partners pull out the wee container with tiny grey green puck of dried out mud that needs soaked and left for an hour just to make it workable.
It's easy to forget that you had to learn something that you've been doing for years, especially something quite simple. But for people who're newer to the sport or have just never done certain things before, some things can seem a bit mystical or intimidating. If you don't know how to do something, you don't know how easy it is. Fortunately for those who want to learn, the process couldn't really be much simpler. All you need is some fuller's earth powder, some washing up liquid and a little glycerine. Stick the powder in a round tub for mixing, and mix in the detergent until you have a consistency you like, then mix in a small amount of glycerine- much less than the amount of detergent. I like it to end up like a soft putty or clay like consistency, it should be a bit clingy to the touch. I've never measured exact quantities and the amount of wet:dry ingredients will vary depending on the brand and humidity where it's being mixed, but I start with 2 large heaped teaspoons of fuler's earth for every 35mm film container I want to fill. It takes about 10 minutes including tidying up. I just put a video on my YouTube channel showing the process.
The real reason to make your own is that it's just so much better than any you can buy in a shop, unless they make their own too. The homemade stuff really sort of grabs the leader or tippet as you pull it through and does a great job of taking off the shine and any grease or floatant that may have contaminated the mono. The other thing is you know it's not old, the week before I filmed the mud making, I bought a tub of Loon Snake River Mud, probably one of the better commercially available leader sinkants. When I opened it it was quite hard, not totally dried out but definietly needed some wetting to make it any use. Rubbish. Mine get replaced when they run out, or once a year if they last that long. They often don't last the year, as when it's so cheap, easy to make there's no reason not to be very liberal with it.
I really can't think of a reason not to make your own, 10 minutes a season for a far superior product that costs pennies instead of buying something that doesn't work as well, seems like an obvious choice to me.