i've had the old morro for years and years -- always had some trouble patchin' the damn thing -- so just bin the old disc and goty steam?
If you want the expansions, but can't find them on CD anymore, then yeah. (since the CD expansions are quite rare now)
But the GoTY version can still be found on Ebay, etc.
Although it's going to cost you more than $20
There's only two legal ways to buy a digital Morrowind. Steam or Impulse. For $20
Steam is highly recommended, because Impulse (the Gamestop version) adds DRM nonsense that conflicts with the Code Patch.
Not sure what you mean by troubles with patches, but GoTY does come with all official patches. And both of the big community patches require you have GoTY, (or both expansions with the final official Bloodmoon patch.)