You can try to run your own website, to save 10% fees on a minuscule userbase, it simply doesn't cover the costs.
Stripe gives you a basic solution to accept payments in some locations and under some circumstances. Once a company reaches in the tens of millions in yearly turnaround or expand internationally, it has to move on and run multiple payment providers.
Steam helps you with that. You could try to do better yourself but the effort is not worth saving a few percent of fees (on a lot less sales).
It takes at least 10% commission to be able to run a company of this type. It's possible to run with as low as 5% in some niches, given a very lean operation and a billion dollar scale to amortize fixed costs. Eventually most of the company will be devoted to customer support and billing related tasks.
There is really not that much that can be shaved off. Small studios could never make a platform any efficient. A small group could spend all their time working on distribution and billing, never shipping an actual game. It's a really good deal to just use steam instead.
For AAA games it's annoying to pay 30% and they're rather make their own platform, that's why steam is dropping commission to 20% for top selling hits.
It certainly won't translate the game for you, not that translating a bunch of text files is the hardest part, but it will help with everything else.
Ask international users what they think of other platforms. Like the one they couldn't use because it didn't accept their names with an accent or couldn't enter a billing address without a state.
OTOH if the game is in Japanese and only sold on a Japanese internet platform then you have two barriers - language and payment
It's better than nothing but it's in no way comparable to what steam offers.