So many web providers offer a complicated range of products that can be confusing even for tech savvy customers. Kinsta is very straight-forward--they only deal with WordPress web sites.
Pretty much any web hosting provider (e.g. GoDaddy, HostGator, etc.) can support WordPress. But providers like Kinsta automate a lot of things that would otherwise require a bit of work to setup: scheduled/automatic backups, virus/malware removal, and uptime monitoring.
Kinsta also offers SSH access, DDoS protection, SSL/HTTPS, page caching, a staging area for web development and testing. What's more, they promise to help fix your site should you end up getting hacked (despite their best efforts to prevent such an event).
The cheapest Kinsta plan is $30 per month and you are limited to 1 site/domain with 20,000 visitors per month.
The market is flooded with cheap web hosting providers that promise unlimited sites with unlimited traffic and storage for a couple bucks per month. So it can be jarring to see a company like Kinsta charge such a steep premium while imposing strict usage limits.
But there are few things you should consider.
The true cost of low prices
Many web hosts entice new customers with really low prices--usually in the form of a steep one-time discount along with additional discounts if you pre-pay for years of service.
But after the initial invoice the price goes way up. Admittedly, these companies usually make it pretty clear that the initial price is a discount (and they list the regular price along with the new-customer price.) But, people are often blind-sided when the real price kicks in.
I suspect it's because many customers pre-pay for two or three years of service at a really attractive price; Years later, when the renewal payment is due, there is some serious sticker shock.
Moreover, super-cheap providers tend to offer mediocre or abysmal service. You can hope for the best. But if you pre-pay for years of service to get a good deal, you're taking a gamble because the standard-money back guarantee only lasts for 30 days.
Discount providers--that rely on really low prices to attract customers--tend to be the worse. Companies with mid-range prices tend to be reliable.
Unlimited web hosting
Traditional web hosting providers promise "unlimited web traffic and storage," but that is usually an empty promise. They depend on their customers creating modest web sites (with a only a few pages and images). Even if you comply with the restrictions in your terms of service agreement, a discount provider can (and will) kick you off if your web site exceeds your provider's assumptions/expectations. (Or they can force you to upgrade to a much more expensive and complicated service plan).
Providers like Kinsta and WP Engine are more trustworthy because they have clearly defined usage limits. (e.g. 20, 000 visitors per month.)
30-day money back guarantee
If you have an existing WordPress web site with some other provider, Kinsta provides software to automate the transfer to their service.
Kinsta vs WP Engine
Kinsta and WP Engine are pretty much identical in terms of features, service and prices--except, Kinsta offers a wide range of service plans while WP Engine only offers three packages. Kinsta has clear pricing for sites that require hundreds of thousands (and even millions) of visitors per month. But WP Engine requires potential customers to contact sales agent to work out a price quote for a site that will receive more than 400,000 visitors per month.
There's nothing magical or special about Kinsta--pretty much everything they offer can be implemented on any WordPress site using free plugins/software on a moderately priced web hosting service like LiquidWeb or SiteGround. But you'll need to know what software to use and how to set it up.
If you don't know how, then you'll have to learn. And you may not know what you need to know...and that can be dangerous, especially if your web site is more than a hobby. A broken web site can cost you money. That's why people use services like Kinsta--because it can be cheaper than hiring a consultant.
Companies like Intuit and TripAdvisor have many clever tech people working for them and they still use Kinsta for their web hosting needs rather than managing WordPress on their own.