Re: Web app? No thanks.
As has been commented, you wouldn't do high end video editing on a PWA, that's ridiculous and offline use is available and pretty seamless.
Think of about 25 years ago when companies used to create PC applications to download to view their product catalogue or even early purchase of goods etc. You would never download an application from a company onto your PC nowadays - just to see marketing information or a function specific to that company. Even most general applications are now served over the web - for some of our users all the applications they use are web based.
So imagine a situation for a company that has a good web presence, an ecommerce site, useful tools and functions a backend that has api links into third party products. Your marketing department now want 'an app'. Marketing: "we need an APP", You: "Why?", Marketing "Everyone has an app it's embarrising we don't have an app".
You now have a choice, go to an agency to build an app in two different flavours that duplicates 80% of what your website does only you need to create separate version of it for each mobile platform and get it accepted by an app store and risk that any fees on it have to be paid to the respective app store owners. If ever your third party links get changed significantly you have to update all versions at the same time and disable all the old versions that people may have. All information and data needs to be update the same on every platform - web/apps. Your marketing department when they change web information using their CMS now need to add requests into the app agency to make changes as well and publish a new version.. etc...etc
Or you can wrap the website in an app skin, or read in the CMS information from the database directly and remember to test all changes to the information on every platform...or...
Yo ucreate a responsive website for your web that works perfectly on all platforms and utilise PWA on the mobile side to add app like functionality such as an app button, offline use, GPS, notifications etc with one code base to maintain, one web development team, one CMS, write once run anywhere etc etc.
The PWA part just means you don't have to go native for when the marketing department says "But we have to have an app as we want to use xyz functionality of the phone".