Signatures are never useless because you never know who may meet whatever malware out there in the world.
If you think wisely, old signatures are taking space on my drive. Old signatures must be in cloud and the most recent, newest malware signatures must be in database. Malwarebytes does this, Avast does this.. they keep last 3 months of samples signatures in their db.
All these 50million signatures running in my RAM.. openin folders with full of .exe files takes time day by day... signatures are growing... Never ending story.. What will happen in 2025 ? 150million signatures as local database, it will be 1GB file

We need more generic signatures and powerful heuristics... these are my opinions but Comodo can continue with old techniques..