It makes sense if you don't have the money to participate in the...

It makes sense if you don't have the money to participate in the SPP. However, it's very likely the SPP will be oversubscribed by a lot since its a hot sector. While Kogan isn't BNPL, it's also in a hot sector and the SPP was so oversubscribed that people were only allocated like 15% of the shares they applied for. So apply for $10k worth of shares and get $1.5k worth of shares, all the while your $10k is tied up with them until they refund you the $8.5k.

So there to summarise, yes its doable, but no you'll likely won't get more shares and will likely have to buy a heap back at market if you want to hold the same amount as last time. On the plus side, the shares that you do get allocated will instantly be in the money, by a fair margin.