No. 2 Fragments is not worth 200 seal scrolls. Save it toward the next 300 rebate.

Technically it could be- if you're purchasing your scrolls, then yes- You get a Hashirama fragment every 30-50 seals that's accurate as I could get it.
If you're saving your seal scrolls, then over a long period of time, the 200 saved toward a 300 rebate is going to be more beneficial in gaining your SR, we're talking about roughly 2500 on the low end, to 3000 & upwards to complete Hashirama, unless you're spending that's nearly 2.5 years away it's not worth it unless you're spending, at least that way you're gaining those Extra Hashirama fragments..