Powershell is an amazing shell scripting language. But it's a terrible daily driver of a shell. Everything is an enormously long line to type. Yes you can make aliases for common stuff but that's non-standard and not portable.
The primary purpose of a shell is not scripting. It's meant to be interactive. Powershell is too heavyweight to be be a good daily driver for a shell.
What do you mean by "not portable"? the alias script sits in a file and can be kept in source control, to be downloaded to any computer you land on. And many pw commands come with readymade aliases that are standard to the base install.
If you're after interactive use, then by all means define and use your own aliases (or functions) as you see fit. It'd be a pretty crappy idea to not do that. Custom aliases in scripts you share with others are not a good idea, of course, but that's firmly in the scripting aspect you note, not the interactive shell use.
That being said, even with commands being long, tab completion does an absolutely amazing job of shortening what you type. Also it's usually just the first command of a pipeline that doesn't have an alias because after that you tend to use the same few cmdlets over and over again (%, ?, select, ft, ...), which do have short aliases.
The primary purpose of a shell is not scripting. It's meant to be interactive. Powershell is too heavyweight to be be a good daily driver for a shell.