NiFe cells have their merits, especialy long life and freedom from damage by deep discharge or being left discharged.

The main drawback is the great variation in voltage between on charge and on load, near the end of discharge.

To fully charge a 10 cell (12 volt nominal) battery can take 18 volts or more. Very few 12 volt appliances can tolerate that.
At end of discharge the voltage would drop as low as 9 volts, which is too low for most 12 volt appliances.
The corresponding range for a 12 volt lead acid battery would be from about 11.5 volts up to 14.4 volts, a much smaller range.

One could of course use a voltage regulator, but that adds extra expense, complication, and risk of failure.
Alternatively one could use a 125 volt battery, and use this only to power loads that accept a wide range of input voltage.
Many electronic appliances and electronic lighting ballasts work from 90 volts up to 277 or higher.
They should be fine on a battery that varies from perhaps 95 volts up to about 200.
Such DC voltages are dangerous and not recomended for the novice.