This question is quite common and always opens a can of worms on here. Let me first say, this is my opinion, nobody really knows what additives are in HM oil. Some brands use words like "nourish", "condition" and "rejuvenate" seals. Some on here say they go back and forth between HM and regular with no I'll effects.
A couple years ago long time Auto Week contributor Stuart Goss said on the show..
Needless to say, BITOG erupted with opinions. Most claimed he was misinformed. Seeking clarification myself and others went to the Official (and recently deceased so you'll have to take my word for it) Mobil 1 Website FAQ asking questions and looking for answers. To my surprise, terms "seal sweller" and "swells seals" were used repeatedly by whoever was answering the Mobil 1 HM FAQ. Again, that website was merged or removed by Exxon Mobil recently. The FAQ no longer exists. I know what I saw. I used M1 HM in a high mileage old Camry with bad valve seals I used to own for years. Worked well, consumption went down.. I changed back to a regular oil as a test. Startup blue smoke and consumption would gradually come back over a few oil changes.
So I personally would not use a HM oil unless it was to run a car with seal problems long enough to trade it in. Its not clear if the seals are being swelled, nourished, rejuvenated, or whatever other marketing terms are used by different brands of HM oil. Modern oils are far superior to a few years ago, I would just use that.