how to convince employer to apply for GC after my L1A

how to convince employer to apply for GC after my L1A - what reasons / logic should I offer beyond the point tha it shows mutual long-term committment. I am very well educated and would like to think in demand in US job market.

You can tell them that green card helps in easy travel in and out of US (if jobs requires so), and gets rid of 7 year cap on employment term.

Downside is that employer may fear that you would leave them after getting the green card, it would be an expense for them and may decide not to return to home country later.