That tariff does show up on the Bulb home page in the “where are Bulb competitively vs the ‘big 6’ standard tariffs” chart (to the right of Bulb, as it’s calculated to be cheaper).
And the actual tariff details you’ve got do seem to bear that out, so it’s up to you whether you think it’s worth switching.
All the BG deals appear to be fixed price contracts, so while you know the rate cannot go up, it also cannot go down (eg if gas wholesale prices fall further) - I’m just mentioning this so that you can weigh that element for yourself as part of your deliberation.
One last thought - while you might be able to renew the contract, I’m pretty sure that BG will not guarantee to offer the same rates at renewal! (they might, they might not - it will depend on the market at the time - bit like car insurance)