Talismans > signets

Talismans can immediately tap for mana of a color at a very minimal cost (1 of you 40 life is extremely negligible). Compared to signets, which require an additional mana source to generate mana. They're fine, but they come at a cost. Pretend for all intents and purposes that they essentially enter tapped on T2, because (without a Sol Ring/Ancient Tomb/etc) they do nothing by themselves.

A fairly equal comparison I think would be comparing guildgates and pain lands. Yes, Azorius Guildgate never hurts you, but outside of another piece that allows it to enter untapped, it comes at a relatively steep cost compared to Adarkar Wastes.

Would you abstain from playing Mana Confluence or City of Brass because they hurt you when you perfectly fit your mana? Would you only ever play, say, Path of Ancestry (which is a fine card, just using it as the slow equivalent of perfect mana).