Well most of it already got covered by Gessler so I'm just adding few of my takes to it
In an actual amphibious invasion scenario what is the use of such a type of drone( wide straight wings, air to surface weapons )?
Have you heard about a lady called called Sümeyye?
Most probably not, so let me just tell you both her current full name and what it used to me before her marriage; Sümeyye Bayraktar and Sümeyye Erdogan.
Yup, those two surnames are exactly what you're thinking of.
So to answer your question about the actual use case of using a small MALE drone from a LHD...it helps the president in gaining traction among the local population when you present the fact that your one the very few countries to achieve this feat.
As for some actual technicalities, here's few points
> If you have a semi-aircraft carrier and a drone then why not make it carrier capable? It won't do any harm
> They can use it to mature the systems like automatic landing that would be used in future on Kizilelma or maybe even Ka'an
> They don't have an aircraft carrier, nor they're going to have one in near future so these LHDs are the only thing they have to do any kind of power projection
> Having a low cost UAV on a carrier is always good as it frees up your fighters to do more of fighter job. Currently if USN Fifth Fleet decides to bomb an ISIS leader in Yemen then for that too the only option they've is a full on F/A-18E/F.
> For small ships like LHDs the options are really limited; either helicopters of your choice or F-35s...that's it. So by having, let's say a TB3 you can do SOME (this point is important, some not all) roles of them better than them.
> In case of beach landing these can provide a better surveillance, reconnaissance, limited attack capability than other platforms. Can act as communication relays in a degraded environment.
OTOH they have one more that is like a stealth fighter jet, if such a drone is launched, can it do CAP vs enemy fighters?
Does it? No
Can it? Yup; maybe better than humans
There are two aspects of aerial combat; WVR and BVR.
Let's about the simpler first; BVR. From an implementation point of view it's extremely easy. So easy that you can even take a commercial plane, add a radar, few missiles, some targetting algorithms and you'll have a formidable BVR platform. So technically any drone that can be equipped with a good radar and can carry BVR-AAMs is worthy. And Kizilelma definitely does both.
As for WVR, the first notion is that it won't be used in future combats. But for this argument let's assume it'll be. Contrary to what people think in WVR combat the pilot is not fighting the enemy fighter, rather he's fighting himself. His skills, situational awareness, reaction time, tactical planning and most importantly, his ability to function properly above 9g is what defines whether he'll win or lose. Replace the pilot with electronics and now your jet can theoretically go beyond 20g. Replace the manual control with an AI autopilot and now you can defeat even the TOPGUN pilots. Infact from as back as 2020 AI pilots have repeatedly defeated human ones in simulated combat in DARPA's Alpha program.