Amortisation is of less interest than depreciation (itself excluded from many measures) because it relates to intangible assets, and it cannot be used as even a rough proxy for replacement cost.
EBITA is used in similar ways to other profit measures such as EBITDA. The commonest valuation ratio that uses EBITA is EV/EBITA. This is similar to EV/EBITDA apart from the inclusion of depreciation as a cost. EV/EBITDA is usually preferable.