401(k) is a place to play the market, which is a lot like playing poker: it's not the cards and the luck that make you win or lose, but rather the other players shaking your inexperienced ass down so you make bad decisions and lose all your cash.
It's not really much like poker, because it's not a zero sum game. Stock value has gone up fairly steadily over a century. Sure you can find ways to lose money if you're trading actively and poorly, but passive stock investment has outperformed other investment options consistently for a long time.
To be clear, I'm kind of "you in the future". I paid off my first house when I was 28 or so; I also started investing in stocks. The money in stocks did a lot better than the money that paid down my mortgage (you can measure this easily; interest is interest - and when mortgage interest rates are as low as they are, they're not hard to beat). It's riskier too, but when you're young is the right time to be taking that kind of risk (assuming you have your basic obligations covered); over time, stocks will win out, so they're the right choice for long term investment even if they may entail short term setbacks.
I mean, say 5 years ago today you had put $50,000 into a vanilla ETF (we'll say QQQ). You'd currently have $128,860. I didn't cherry pick that or something, I just picked a round number time frame and an extremely common ETF. In the same time as you gained $78,000 on stocks, you could have, instead, saved $10,000 of interest on a 4% mortgage.
That's not to say that there isn't other things worth doing. Maybe you want more education or windows or who knows what. Lots of things can make sense. But eventually, you'll almost certainly want money in the stock market if you're ever going to retire.