In France we have this tax deduction thing only since a few years ago, well there was a form of it before but the money was stuck until retirement age no ifs no buts the only exception being personal bankruptcy, so that wasn't an option for me, but now they have relaxed the rules.

I have however with my job a tax free thing where I get "matching contributions", so I put the max in there (5400€/year). I just started the aforementioned thing, that lowers my income by as much as I put in it so I get taxed less, and my job also contributes some to it, so that's free money.

Like LoyceV I see it as diversification, that helps me hodling BTC. And for example I'm looking at houses and plan to spend all/most of that fiat stuff but none of my BTC stash to buy it.

Also as long as I'm here the taxman is taking a huge chunk of my paycheck to give it to retirees so in theory I'll get a state pension out of that, although I'm not sure the system will still be there by then and I plan to retire 20 years early so that will probably not work, let's say it's plan C.