As far as I know Buff Sebrights aren't standardized in the US so technically they can't be "show quality". There are some people working on them. Saw some on Sale Row at a recent show. They needed a lot of work & I imagine these are the same. If you're looking for a long term project & want to be one of the people who help get them recognized go for it.
As to their value, that's really up to you. Chickens don't have an absolute value. Their value is determined by agreement between buyer & seller. So, if you like them & are willing to pay $25 for them then that's what they're worth.
Awhile back a Silkie sold on EGGBID for $600 or something like that. Someone thought it was worth that much. I wouldn't have paid $6 for it because I don't like Silkies so it wasn't worth much to me.
No one else can tell you what a chickens is worth-they can only tell you what it's worth to them.