When I win significant sums, I do buy things with them. This year I had solar PV fitted after a big win. In a way, this is a 25 year investment due to a government backed "low carbon" scheme because I am paid by the government for generating my own electricity. On top of this, I buy less from the energy company, and even get to sell them my daytime leftovers. It is similar to buying a bond that pays around 10% per year on the capital invested for a fixed 25 year term. The payments are also index linked to inflation, so rise every year we have general prices going up. The panels are far too big to fit through the monitor when I have casino banking open so they cannot be donated back to the casino. An earlier significant win allowed me to pay off the remains of my mortgage early, and also get out of the endowment shortfall trap that hit many mortgage payers.
This year, there is still a fair chunk left to spend, and this is separate from the chunk in Neteller that is available to be donated back to the casinos. Much of it is earmarked for a garden room extention to the rear of the house, and another big chunk has been invested into the UK's ISA investment scheme, a means to hold limited investment each year completely tax free, and to provide a bail out fund should any disaster strike.
I have also bought myself a top of the range laptop, and one niece a mid range laptop for college, and about to buy another niece something similar for university. I could do with a new desktop gambling PC too, and will probably be getting that this Autumn. New bathroom and kitchen is also planned.
It is the smaller wins that tend to find their way back to the casino over time.