As a Software engineer who has built applications inside and outside of NetSuite, i wanted to hear everyone's opinion on NetSuite exams

IMO I'd only get them if you are forced or there's a reason to do so. They aren't particularly useful for anything but warm and fuzzy feelings for people. They are not particularly difficult and if you have access to the learning portal, it's pretty trivial once you do the exam prep (or have some experience). Personally, I've had foundations/dev for about a decade and not a single person has ever really cared that I got them.

As I have opened my own consulting firm , will it attract clients ?

That would depend on if clients want the certs or they don't care. Do they care? Go for it. Do they not care? Don't waste your time doing it. Just comes down to what is needed really. It never hurts to get them, but is there any gain from doing it in the scenario? Really just varies client to client. If you have your own firm, it may make sense to get them just to check the box for any future engagements.

I agree with @creece , with that being said, some partners and consulting firms use it as a marketing pitch which I find useful, I worked for a partner where all developers and consultants were certified, while that alone does not guarantee quality or knowledge it does look very professional. People do not care enough about the certifications but they should in my opinion, even if they are not very hard or difficult those do bring some specific knowledge about the system which I think is very important. I would mention a quick example: The amount of custom fields people create without using filters is crazy and as those grow the system becomes slower and slower and to be fair it is not a NetSuite issue it is a user problem. If you create a List / Record Transaction custom field you probably can add some filtering to specific subsidiary and/or transaction type, that will speed up that field behavior overall, but nobody does it.