Chandler, perhaps a better way to discuss precision levels is to tell you what the overall procedure is, so that you can understand the role a good level plays.
Leveling a lathe simply means we are trying to get the ways of the lathe to be co-planar so that there is no twist across the bed. The reason we do this is because an un-level lathe will turn a taper into your work piece. The way we remove twist is to use a level across the ways at the headstock end and at the tailstock end and use leveling adjusters under the lathe, under the stand or both. When both ends of the lathe are level that indicates that both ways, front and rear, are in the same plane. Typically, using a level like this will get your lathe very close to level but it may/probably will still produce tapered cuts unless you fine tune the leveling even further. The way we do this is with a 2-collar test that allows you to really fine tune your levelers to ideally remove all evidence of a taper in the work piece. Go look up the 2-collar test to see how this is done. When both collars are the same diameter after test cuts, the lathe is level. Know that all lathes move and a preliminary leveling must be repeated in a week or two and then checked every so often to make sure nothing moves.
Now, with that background, the role of a precision level is the same as a less precise level. For example, a Starrett 98-8 is sensitive to 0.005"/foot, whereas the level you showed above is sensitive to 0.0002"/foot. As noted by the other guys, a 98-8 is not all that sensitive but it will still get you close enough and you can use a 2-collar test to get you the rest of the way. The advantage to the more sensitive precision level is that it will get you closer a lot faster, so that you will do far fewer trial cuts with your 2-collar test. This may not seem like a big enough difference to justify the cost of a precision level but it can mean hours of saved time, literally.
I have both a Starrett 98-6 and a Kinex precision level sensitive to 0.02mm/Meter and the difference in time that the better level saves can be significant. I use the Starrett to get me close, then switch to the Kinex to get me closer. When the Kinex says I'm level, I am maybe one or possibly two cuts away in a 2-collar test to dead level, and we're talking about resolution in the low tenths to zero over a 10-12" distance.
So, think of the need for a precision level in terms of time and frustration. The more sensitive the level, the less time you will spend doing test cuts.
As for your bench, as long as it is solid and the whole top provides a stable platform, it should be fine. Just make sure you have some way to level the lathe and the stand so you can make the adjustments you need.
