Ask HN: Should I join a startup that will match my salary

I am being offered to join a startup (post angel round, pre series A). This startup is offering to match my (slightly above market) salary.

They are taking the product into an overseas market and creating a child company there. I'd be a key member in leading these efforts (from marketing and sales to product development). Some aspects of the product (including the main business model) will be changed to adopt to the new market so in some ways it will be like starting from ground 0 which, needless to say, comes with it's risks.

I'm being offered my current salary. I can use parts of or all of it to buy parent startup shares at approx 17% discount. I can at a later date exchange those shares for child company stock once an official valuation is available (e.g. after an angel round). Initially I'd be capped to not be able to own more than 10% of this child company.

The offer sounded a little convoluted at first but on the surface it appears that between my current situation and what I'm being offered the only monetary advantage is the ability to purchase the startup's stock at 17% discount and later being able to exchange it for a new child startup that I'll be a part of.

Is this a worthwhile offer? Thoughts/opinions appreciated.