I'm very happy with my Makita track saw though that, while still pricey, was maybe 1/3 the cost of the Festool?
You primarily see their tools in the hands of pros, because their tools are, in many cases, better than the alternatives. The value prop on the Domino isn't that it's the strongest joint, it's that it's strong enough for the application, fast, and repeatable. When you build furniture for money, that matters. You don't have to build too many frame and panel assemblies to make it pay for itself.
The dust collection on their sanders is outstanding. I don't do site work that involves sanding, but if I did, you'd better believe that I'd make that investment in a heartbeat. Not getting fine sanding dust all over your client's space is worth every penny of the cost.
The track saw (or like, a drill/driver, but that's a bit jokey) is probably the one place where Festool has the least delta, IMO. The Domino, their sanders, and their dust extractors are genuinely a cut above, and while my shop is outgrowing the basic MFT that they sell, it's mostly to build my own, bigger, more rugged one.
They are also head and shoulders above any other biscuit joiner I've used. At the price, they should be. I don't own one, but I have used one in another shop.
It's hard to describe just how much more useful the tool is compared to router jigs, pocket holes, etc. It changed how I design my work, how I prepare rough stock and cut it to final size, and how I work with wood movement.
[1] though I have the Seneca adapters and all that, I wish I had gotten the smaller one. Unless you're doing serious structural joinery the smaller Domino is much more convenient, and you can double up on tenons instead of reaching for a bigger one in most cases anyway.
I'll add it to my "Wish List", haha.
You’ll know it if you need the larger domino, like if you’re selling a few heirloom quality beds a week for four or five figure sums, and then the expense will most likely be an afterthought.