It seems to me that In lightning ecosystem the most trendy app is Wallet of Satoshi. I think it is because it is cheap, simple, and fast. Every app is trying to be simple and fast, but lowest cost is the strongest differentiation here.
There might be potential even on first layer to crate a solution that will be cheaper then others.

Imagine wallet that

• Selects lowest fee as a default
• Combines more transactions into one

Primary selling point of this activity would be low fees, but it would increase privacy/fungibility significantly as a byproduct

Related ideas:

• Joinstr - Coinjoin without central coordinator with communication via Nostr
• Discrete payments - via Wasabi payments and Nostr communication
• Cross-Input Signature Aggregation (CISA) - proposal to lower the cost of mass transactions even more

Any thoughts? Anyone interested to participate?