OK for inexpensive chips, but:
¶ no free tracking, which you get with the $2.66 PayPal snipping labels for first class PARCEL mail..
¶ you are paying letter rate, so mail piece must be no more than 1/4 inch thick, so not as strong/protective as sandwiching the chip between bubble wrap and strong cardboard the way I do with first class PARCEL mail (over 1/4 inch thick; $2.66).
¶ note: a while back someone recommended sandwiching the chip between the hot cup holders you can find at Starbucks, for example, so mail piece no more than 1/4 inch thick and eligible for cheap first class LETTER rate.

Robt.