In general yes, but if I look at the apps on my phone I have
A mail client, K9, old UI. This clearly can't be replaced by a web app because I'm using it to look at my mail in a few POP3 servers and then I'll download those messages on my laptop (Thunderbird)
OSMAnd, offline maps and trop recording. Can't be web based.
Password manager, with a local dB synced with Syncthing.
Syncthing.
Epub reader, from files stored on my phone.
Photo gallery, for files on my phone. I backup to my laptop with Syncthing.
Banking apps, that I must use for 2FA in the web sites of those banks.
A network scanner, useful to debug networking issues.
Etc.
Of all the apps that are currently installed on my phone the ones that could be web apps are:
Go4Go, to view game records of pro games.
Elementary.
Chwazi.