A lot of models with Stealth, particularly among Azur Prowlers, also have powerful Actions contingent on them being Hidden.
However, this is where things become tricky for the player managing units with Stealth. For a start, Stealth requires Upkeep, meaning that assuming a move plus Hidden-based Attack plus Upkeep, will mean that the Prowler probably has no AP left for Dodges etc. after they have Attacked. There are exceptions like Kagemaru whose AP limit is 5 and who can maintain Hidden if using basic Attack or Charge.
In addition, these units are usually quite fragile with low to middling Life Points and usually no Armor. Therefore, when they Attack from Hidden, they need to time it right to minimize risk afterwards. This is compounded by the fact that when a model Attacks from Hidden, the Hidden status is usually lost; therefore resuming Hidden through Stealth means paying the full AP costs, and requires the unit to be outside enemy Control Zones.
Figure 1: If The Type-004: Hellhound wants to Seek (try and find Hidden models in its Control Zone), it would only be able to find Kyler since Juliette Kaim is out of LOS. The Hellhound is a better choice than Arkham to Seek as it gets a bonus for being a Prowler.
If both Kyler and Juliette Kaim wanted to use Stealth, only Juliette could so because she is out of LOS.
The game management around Stealth is one of the things that I like about Anima Tactics; each Organization favours certain troop types, which in turn creates certain play-styles. Azur certainly has a dominant Stealth-based play style among its earlier models, although as their line-up has been expanded that has changed.