Two things to consider.But on the other hand, I can solve it using external drives.
Same with me. 512GB was enough for me to store everything important on the drive. With a 1TB I'd still have to put some data on an external drive and you need a backup anyway so, I could not justify the price for the 1TB internally. 256GB would not be enough for me but 1TB is just not worth the money for me.
You can still sell the MBP and in theory the blade ssds should be easily swappable. It isn't integrated into the logic board like RAM.