cheap monitor as field monitor

is there any big reason why I shouldn't buy this as field monitor?

https://www.amazon.co.uk/gp/product/B01HR7TYYQ/ref=ask_ql_qh_dp_hza

it doesn't have battery, but I think it works with a power bank (checking) through usb. It doesn't have a shade, but I can build one maybe?

Says on the advert that it needs 12v dc. Most power banks are for USB, 5v only.
I think you will need a 12v battery I'm afraid. 10 x nicads or the like would do the trick.

but down in the description it says:

Support USB interface to charge (5 volt 1 amp)

You can run it with a 12v transformer. That's how I use mine. If it's talking about 5v usb charging however, this suggests an onboard power supply of some sort?

Hi someone asked that question in the Q and A
And they say no
It comes with a power adapter can you use a 12 volt inverter on you car battery

It was me to ask the question The cheapest field monitor is 99 pound so I wonder if it's worth the difference

Yes I guess that explains it. A field monitor with battery can be useful for outdoor though. Too many times I thought the image was good to then be disappointed once opened on pc ( mainly micro blur or out of focus)

Eventually I am inclined to buy this one

https://www.amazon.co.uk/dp/B01H2ZUZLO/ref=cm_sw_r_other_apa_p5ZZAbZD1P420

If it works how assume it should work I know it will improve my worflow. I am still reclutant to spend that money though especially since we got image sync which is anyway to slow to show the full res image. I guess there is no hope for a cheaper solution anytime soon anywya